Politics of Alliance before the Swabian League

The Swabian League emerged from a culture of alliance-making among Imperial Estates that stretched back into the Middle Ages. Numerous regional peace-keeping leagues cropped up among the Empire’s territories from the thirteenth century onward.Footnote ⁵ While many of these alliances were short-lived, their activity shaped the 1356 Golden Bull, one of the foundational documents of the Empire’s constitution. The Bull confirmed the right of Imperial Estates to form alliances with each other as long as such agreements served “the general peace of the provinces and lands.” In theory, such alliances had to meet with imperial approval and could not be directed against the emperor.Footnote ⁶ In 1495, the Imperial Diet of Worms further clarified these restrictions by forbidding both the emperor and Estates from “making any alliance or union with foreign nations or powers that might damage, disadvantage, or work against the Empire.”Footnote ⁷ Nevertheless, during the fourteenth and fifteenth centuries, efforts to prevent leagues from forming often came to naught. All types of Estates made use of alliances and other associations, which they framed as tools for mutual protection and conflict resolution. These arrangements often included a limited duration and exempted certain opponents from their jurisdiction.Footnote ⁸ They were so widespread during this era that Duncan Hardy has referred to them as a “universal format” of political organization in the late medieval Empire.Footnote ⁹ Much as the Swabian League shaped its successor alliances, the proliferation of late medieval associations set patterns of behavior that influenced the Swabian League.

Some late medieval leagues were cross-status in nature, meaning they included Estates of differing stature. The Rhenish League from 1254, for example, included several cities, prince-bishops, and minor nobility.Footnote ¹⁰ In the 1370s and 1380s, an ostensibly urban league added some princely members.Footnote ¹¹ The 1474 Lower Union of Alsace, in turn, united princely, knightly, and urban Estates in opposition to Duke Charles the Bold of Burgundy.Footnote ¹² The ability of leagues to bind Estates together for common goals appealed to several emperors, many of whom fostered the use of alliances during the fourteenth and fifteenth centuries. Some emperors even tried to combine multiple alliances into meta-leagues that could better serve imperial interests.Footnote ¹³ While unsuccessful, these attempts foreshadowed policies that early modern emperors adopted toward their era’s corporate alliances. Alongside these medieval cross-status leagues, most associations in the late Middle Ages united Estates of similar status. The 1445 League of Mergentheim, for instance, bound together several princes in a ten-year alliance against the efforts of the Swiss cantons and south German cities to gain increased autonomy.Footnote ¹⁴ As part of its activity, the League supported princely efforts to expand their territorial authority at the expense of nearby cities, as in the case of Count Ulrich the Beloved of Württemberg and his conflict with Esslingen.Footnote ¹⁵

Smaller Estates found same-status alliances particularly attractive, as they promoted strength in numbers among authorities that shared a common identity. Many urban magistrates used alliances with other cities to protect civic freedoms through the collective pooling of resources, and urban leagues popped up across the Empire during the late Middle Ages.Footnote ¹⁶ Some proved extraordinarily long-lived, such as the Decapolis in Alsace and the Six-Cities Alliance in Upper Lusatia, while others survived for only a few years.Footnote ¹⁷ Their charters emphasized each league’s duty to protect the public peace and standardized procedures for mediating conflicts among their members.Footnote ¹⁸ One 1376 alliance, for example, required its members to take any dispute to the league assembly for adjudication.Footnote ¹⁹ Similar structures appeared in many sixteenth- and seventeenth-century alliances, and the language employed in late medieval treaties reappeared throughout the early modern period in a variety of contexts.

Many late medieval alliances enjoyed large memberships. One example is the Swabian City League of the mid-fifteenth century, which claimed thirty members in 1445 and helped lead to the League of Mergentheim’s creation as a counterweight.Footnote ²⁰ Urban alliances were not always successful, nor did they always include only cities. Nevertheless, their existence fostered a culture among urban leaders that made participation in alliances a standard method of promoting regional peace and collective security. A similar movement occurred among the Empire’s lesser nobility, who created alliances for many of the same reasons that cities did. One such alliance, the League of Saint George’s Shield, formed the institutional core of the Swabian League in 1488.Footnote ²¹ This widespread “associative political culture” played a crucial role at all levels of the Empire, with alliances helping to preserve peace and nurture common interests among numerous Estates throughout the late medieval period.Footnote ²² The Swabian League’s activity built on this earlier tradition while reframing its impulses in ways that resonated in the political life of the Empire deep into the seventeenth century.

The existence of multiple, often competing leagues created tensions and opportunities in the fifteenth-century Empire, as the second Cities War of 1449–50 reveals. The war played out as a series of interrelated regional feuds between members of opposing alliance blocs.Footnote ²³ In this way, the Cities War resulted from a dual alliance system that embodied wider divisions over different visions for the Empire’s future.Footnote ²⁴ On one side sat the League of Mergentheim, the alliance of princes that saw concentrating power in the hands of the landed nobility as the best way to preserve peace in the Empire. On the other side was the Swabian City League, an alliance composed predominantly of cities, along with a few princely Estates, that prized urban autonomy and interdependence among cities and princes.Footnote ²⁵ The City League ultimately lost the war, but the unity it promoted allowed its members to preserve their independence and to achieve a better final peace than they would have received on their own.Footnote ²⁶ The league itself even survived, in reduced form, and the ensuing years witnessed several agreements among cities and princes to preserve the public peace on a regional scale.Footnote ²⁷ Ultimately, the Cities War embodied patterns of collaboration and opposition between Estates of different status that persisted across the next two centuries. The contrasting visions embodied in the war’s competing alliances evolved and developed over the sixteenth and seventeenth centuries, but the different goals they espoused remained core tensions of the politics of alliance throughout the early modern period.

The Swabian League’s Structure

The Swabian League marked an attempt to fuse different same-status alliances into the largest, most sophisticated cross-status league up to that point in the Empire’s history.Footnote ²⁸ The resulting structure served as the chief model for corporate alliances for the next century and a half. The League’s initial 1488 treaty united twenty-six cities with scores of local noblemen.Footnote ²⁹ Emperor Friedrich III joined as well, although not in his capacity as emperor but rather in his role as territorial lord of the Habsburgs’ Austrian possessions. By incorporating his hereditary Austrian lands into the alliance rather than the imperial throne, Friedrich sought to maintain the uniqueness of the imperial title while still harnessing corporate support for his political goals. The distinction between Friedrich joining as an Imperial Estate rather than as emperor proved useful for the League’s other members as well, since it ensured access to the emperor’s resources while placing him on an equal footing with everyone else within the alliance’s structure.Footnote ³⁰ This arrangement persisted under Friedrich’s successor Emperor Maximilian I, who took over on Friedrich’s death in 1493. The presence of the Habsburg archduke of Austria made the League attractive to other princes, who began to join in substantial numbers in 1500.Footnote ³¹ The resulting combination of urban, knightly, and princely Estates gave the Swabian League an authority and geographic distribution that exceeded almost every previous alliance.

The entrance of several princely Estates years after the League’s creation underscores the fluctuation in League membership that occurred across its existence. Estates routinely entered and left the alliance. The city of Strasbourg, for instance, joined the League in 1500, only to exit twelve years later in 1512. Despite this fluidity of membership, the League remained an alliance that united Estates of different size, status, and political prominence throughout its almost fifty-year existence. Dozens of minor nobility belonged to it, along with almost thirty cities, including the most powerful south German communes like Augsburg, Nuremberg, and Ulm. While the number of urban members remained fairly stable, the number of princely members steadily increased over the years. By the 1520s, many of the most prominent princes in the Empire’s southern half had joined the League, including the elector of Mainz, the duke of Bavaria, the landgrave of Hesse, and numerous prince-bishops.Footnote ³² The League therefore came to reflect the composition of the Empire’s wider political system right at the moment that it grappled with the pressures of the Reformation.

Renewed and revised in 1496, 1500, 1512, and 1522, the League’s treaty established a corporate structure for formulating and enacting common policy that became a model for subsequent alliances. While its basic organization remained stable, the League’s treaty grew in complexity over time to incorporate an ever expanding array of issues. The number of articles in the treaty increased from a mere 24 in the initial 1488 version to 112 in the final treaty of 1522.Footnote ³³ This rise in sophistication highlights one advantage of corporate alliances: the ability to refine and reinterpret how the alliance operated at frequent intervals. This capability gave alliances more flexibility to respond to changing conditions on the ground than the imperial organs of government possessed, even as alliances often drew legitimacy from their mission to support those same organs.

In the case of the Swabian League, its mission rested on preserving the Landfrieden, or public peace, a concept developed during the late Middle Ages that the Imperial Diet enshrined into law in 1495. The doctrine of public peace argued that rather than employ violence, Imperial Estates that came into conflict should negotiate a resolution that avoided the use of arms. If any Estate violated these principles by attacking another, the aggressor forfeited protection under the peace, meaning military force could be used against them to reestablish peace and order. Because of the fragmented nature of the Empire’s political system, the emperor could not enforce these stipulations on his own, which made the public peace a matter of collective security that groups of Estates sought to maintain together.Footnote ³⁴ The politics of alliance therefore intertwined closely with the public peace. Leagues in the fourteenth and fifteenth centuries constantly referenced the peace as a prime reason for their existence, as they sought to shield their members against what they viewed as illegitimate military force.Footnote ³⁵ The Swabian League built on these earlier initiatives, representing a large-scale experiment at collaborative peace enforcement. An oath taken by all members to aid each other in case of attack formed the alliance’s centerpiece. To ensure their mutual protection, each Estate pledged a certain amount of money to a central League treasury in order to underwrite military mobilization in a time of crisis. If an ally came under assault for any reason, that Estate could request the League’s aid. If members decided collectively that the affair merited corporate intervention, the League would ask its members to pay their appointed fees to fund the marshaling of troops.Footnote ³⁶ Mobilizing this defense structure remained essential to the League’s operation throughout its existence, although the targets of its actions changed over time. In its early years, League members framed their endeavor as a way to resist attacks on the peace by two regional powers: the duchy of Bavaria and the Swiss Confederation.Footnote ³⁷ Not surprisingly, the League’s first major military confrontations involved these two opponents.

The Swabian League’s structure reflected the principles of power-sharing and collaborative policy-making evident in its system for mobilizing aid. Its members organized into three “benches,” each of which represented one group of Estates: the cities, the minor nobility, and League princes. Each bench received equal representation on the League’s Central Council, its main decision-making body. In the initial 1488 treaty, the minor nobility and cities each received nine representatives on the Council. When the League incorporated many princely Estates in 1500, it restructured the Council to give each bench seven councilors for a total of twenty-one.Footnote ³⁸ All members pledged to follow majority rule in the Council, which empowered smaller Estates in ways that no other institution at the time did.Footnote ³⁹ The possibility existed that the cities could be outvoted by the princes and minor nobility, for example, but the Council’s structure also meant that the lesser nobility and cities could team up to thwart princely plans. In addition, the Swabian League established a court to adjudicate conflicts between its members. Staffed by trained lawyers drawn from each of the three benches, the League Court embodied the alliance’s commitment to the public peace, not only by protecting its members against aggression from outside forces but also by regulating relations among members within the alliance.Footnote ⁴⁰

This structure established a balance of power and sense of equality among League members that existed nowhere else in the Empire’s political system, which led some members to lionize the alliance as the “proper form of the German nation.”Footnote ⁴¹ According to Horst Carl, the Swabian League “became a constitutional experiment in the ability to unify truly opposing forces: the leveling principle of majority rule and the hierarchical Estate structure of its members.”Footnote ⁴² Its ability to mediate apparently opposing impulses undergirded the League’s attractiveness, both during its existence and after its 1534 dissolution. Part of the League’s popularity during its first two decades also stemmed from its connection to wider efforts to reform the Empire. The latter part of the fifteenth century witnessed efforts to strengthen the imperial organs of government known as the Reichsreform, or imperial reform movement, which drew heavily on late medieval corporate politics. At the 1495 Imperial Diet of Worms, the assembled Estates, in cooperation with Emperor Maximilian I, codified procedures for imperial diets and established new institutions such as the Chamber Court, many of which reflected the practices and language of late medieval alliances.Footnote ⁴³ The Diet also approved an “eternal public peace,” the specifics of which drew on the Swabian League’s charter, which itself derived from earlier examples. In the process, core principles of the League became institutionalized in the Empire’s structure. Influences moved in the other direction as well, as the Swabian League became a source of support for the reform movement.Footnote ⁴⁴ The individuals who staffed the League Court, for example, often had experience at the Chamber Court, while many officials at the Chamber Court had also worked in the League Court.Footnote ⁴⁵ In certain circumstances, League members could even appeal the League Court’s decisions to the Chamber Court.Footnote ⁴⁶ The Swabian League therefore provided models for imperial reformers to follow, while the results of imperial reform shaped the League’s operation. This reciprocal relationship between the imperial center and a corporate alliance became a persistent factor that shaped how the Empire and its states evolved over the course of the sixteenth and seventeenth centuries.

The symbiosis between the imperial organs of government and Swabian League made the alliance a useful tool for the regional implementation of policies promulgated at the imperial level. The League’s ability to buttress the imperial constitution represents a key reason why corporate alliances proved so popular, especially in regions like southern Germany that housed many large and small Estates. The enactment of regional policies in such politically diverse landscapes could not occur in a unilateral manner. Large Estates needed the wealth and consent of smaller Estates to pursue their individual goals, while smaller Estates gained protection and greater political agency by allying with larger Estates. The politics of alliance offered a way to identify collective paths of action that could benefit all members. As League participants discovered, the collaborative structure of corporate alliances offered a powerful tool for pursuing common interests, especially when that pursuit required the deployment of military force.

The Swiss War and the War of Bavarian Succession

The League’s first major military confrontation occurred with the Swiss Confederation in 1499.Footnote ⁴⁷ The Swiss War, also known as the Swabian War, ended largely in defeat for the League, an outcome that did surprisingly little to diminish the alliance’s popularity. Instead, the League’s expansion in 1500 to include numerous princes and the creation of its three-bench system marked in many ways an attempt to remedy the shortcomings the Swiss War had exposed by strengthening the League’s collaborative structure. This renewal set the stage for more successful military action in 1504, when the League intervened in the disputed succession to the Bavarian ducal throne. The contrast between these two undertakings revealed the League’s potential and limitations as a vehicle for collective military action. The success of any League military operation hinged on the ability of its Estates to agree on a common vision and goal for the campaign. This dynamic shaped the Swabian League just as it would countless successor alliances over the next century and a half.

The Swiss War originated in a series of conflicts surrounding the city and bishopric of Constance in the 1480s and 1490s. Ever since the League’s creation, authorities in the Swiss Confederation had seen the League as a threat to their regional sphere of influence. In particular, the Confederates sought to bar the city council and bishop in Constance from joining the League, since their membership in the alliance would extend the League’s reach right to the Confederation’s doorstep and imperil Swiss claims in the Thurgau region. Accordingly, officials in Constance tried to stay aloof from the League in order to avoid conflict with the Swiss, but escalating jurisdictional clashes with the Confederation ultimately drove both the council and the bishop into the League’s arms by 1498. At the same time, tensions flared between the Swiss and Emperor Maximilian I over Swiss refusals to obey many of the decrees of the 1495 Imperial Diet of Worms, as well as the Swiss decision to ally with the French crown. These various impulses led to the outbreak of hostilities between Maximilian’s troops and the Swiss in early 1499.Footnote ⁴⁸ Maximilian, a member of the Swabian League in his role as archduke of Austria, appealed to the alliance for aid. Arguing that it possessed a duty to aid its member against hostile opponents, the League as a corporate body declared war on the Swiss on January 20, 1499.Footnote ⁴⁹ The League Council condemned what it portrayed as Swiss aggression, which left it no choice but to support Maximilian “according to the power of the alliance.”Footnote ⁵⁰ As the League engaged its mechanisms for mobilization, its first military test loomed on the northern slopes of the Alps.

Similar to the Cities War in 1449–50, the Swiss War consisted of a series of loosely related armed conflicts and regional battle fronts. The League experienced some initial military successes, but its operations quickly faltered due to a breakdown of internal cohesion.Footnote ⁵¹ The League’s collective declaration of support for Maximilian masked skepticism within its ranks about the war’s ultimate goals. While the League Council emphasized the threat to the League as a whole, several nobles and cities perceived the war as Maximilian’s personal project that served his interests alone rather than the common good of all members. Why should League Estates burden themselves financially to support military action, they argued, if the benefits accrued to only one alliance member? Accordingly, some members hesitated to supply the requested funds to underwrite troop mobilizations. In ensuing years, disputes over the financing of military operations became a constant feature of the League’s existence, and similar concerns arose in almost every debate about the use of military forces by corporate alliances over the next two centuries. In 1499, disagreements over the war’s purpose led to delays in positioning troops and significant ruptures in League solidarity.Footnote ⁵² In the field, League commanders complained about a lack of men, money, and firepower.Footnote ⁵³ They also bemoaned the poor quality of their troops, which often left League forces unprepared for combat and raised further questions about the willingness of Estates to finance operations.Footnote ⁵⁴ “It is as if we are throwing our money into the lake,” argued one exasperated urban official, as frustration with poor military planning and infighting mounted.Footnote ⁵⁵ This lack of coordination showed up on the battlefield, as the Swiss routed a force of 10,000 League troops in late February.Footnote ⁵⁶ While the Swiss endured their own organizational and logistical problems, they nevertheless outmaneuvered Maximilian and the League, culminating in another victory in July at the village of Dornach.Footnote ⁵⁷ By the time the war finally ended in September, the League’s internal fault lines, and the problems for collective action that they created, had been laid bare for all to see.

The divisions that the Swiss War exposed made many observers wonder whether enough common ground existed to sustain the League. One urban representative on the League Council, Hans Ungelter, opined in April 1499 that “the majority of the nobles have had enough of the League …. They would likely prefer there to be no League at all, which might well come to pass.”Footnote ⁵⁸ Despite the League’s struggles, however, the pull of corporate alliance won out. The majority of League Estates continued to believe that the League served the good of “the Holy Empire, the House of Austria, and the land of Swabia.”Footnote ⁵⁹ What the Swiss War revealed was not the League’s uselessness, but rather the need to promote greater cooperation among its members. Accordingly, its members reorganized the League in 1500 by introducing the three-bench system and incorporating numerous princely Estates.Footnote ⁶⁰ Coming right on the heels of the Swiss War, this expansion allowed League members to rededicate themselves to a collaborative undertaking whose structure required even greater consensus than its previous iteration had. By addressing issues that had hampered its operation months earlier against the Swiss, the League reinvented itself. Such flexibility in response to new conditions became a hallmark of later corporate alliances and served as a key mechanism for altering the development of their member states and the political systems in which they participated.

The League’s renewed solidarity came under pressure in 1503–4 when Duke Georg of Bavaria-Landshut died without an heir. A struggle ensued for control of his patrimony, during which a League member, Duke Albrecht of Bavaria-Munich, appealed to the League for assistance. Initially, Emperor Maximilian sought to mediate between the disputing branches of the Wittelsbach family without the League’s direct involvement. The League Council supported this approach in the hopes of averting war, but negotiations dragged on for months without resolution.Footnote ⁶¹ Frustrated by this pace, Albrecht’s rival, Count Ruprecht of the Palatinate, attacked and occupied the city of Landshut in April 1504 in an effort to take the ducal throne by force. Ruprecht’s escalation of the conflict marked a turning point in the League’s willingness to intervene. For most League members, Ruprecht’s occupation of Landshut violated the public peace and placed the affair squarely in the League’s domain. They therefore felt honor-bound to offer Albrecht assistance. Elector Berthold von Henneberg of Mainz expressed this feeling when he argued that the League should act militarily to ensure its members fulfilled “their duty, letter, and seal” to protect each other imposed by the League’s treaty.Footnote ⁶² Unlike the Swiss War, therefore, Ruprecht’s actions seemed a clear threat to everyone in the alliance, since inaction would sully the collective honor of all League members.

In response, the League marshalled troops to fight for Albrecht, and Emperor Maximilian threw his weight behind the League. The ensuing war ended in victory for Albrecht. The League’s armies proved indispensable to his success.Footnote ⁶³ Some members still complained about the war’s cost, and Albrecht demanded more troops than the League could supply, but the majority of League Estates saw a fundamental difference between this war and the Swiss conflict of 1499. Ruprecht’s clear violation of the public peace challenged the collective security of every League member in a way that the Swiss War had not. League members were therefore willing to sacrifice to support a corporate war effort, and they bristled at later accusations that they had not done enough to aid Albrecht. Toward the end of the war, for example, Duke Albrecht complained that the League Council had decided to withdraw troops from the conflict prematurely, “all because of the League’s negligence.”Footnote ⁶⁴ In so arguing, Albrecht hoped to convince the League to keep troops under arms in Bavaria not just to defeat Ruprecht but to help Albrecht establish his own rule. This demand, which would have shifted the League’s involvement from protecting the public peace to advocating for personal dynastic politics, met with stiff resistance. The League’s assembly dismissed Albrecht’s charge, arguing that “we have behaved in every way … just as we are responsible to do under the terms of the alliance. We will continue to do so in the future, as much as our means allow.”Footnote ⁶⁵ From the perspective of its members, the League had fulfilled its duty to Albrecht by protecting the public peace. It had lived up to the ideals enshrined in its charter, but it would not overstep the boundaries of action imposed on it to allow its exploitation for individual gain.

The League’s performance in the War of Bavarian Succession marked a dramatic improvement over its war with the Swiss. The main difference lay in the fact that in 1504, most League Estates believed the common interests of all members necessitated involvement. In 1499, military action seemed primarily to benefit Maximilian, while the lion’s share of hardships fell on League Estates. In 1504, Ruprecht’s violation of the public peace made the affair a cause of common concern central to the alliance’s mission. Even as they squabbled over money, therefore, League Estates displayed solidarity and were victorious on the battlefield. They intervened for Albrecht not to bolster his dynastic strength, but rather to achieve the goals of collective security laid down in the League charter. Once this had been accomplished, the League withdrew its troops, even as Albrecht sought to use those forces to consolidate his individual position. The Swiss War and Bavarian War showed that the League could marshal formidable military resources, but only if alliance members felt unified behind an issue of common interest. Over the next 150 years, this relationship between military success and a shared vision for action came to define the military experiences of many leagues.

War in Württemberg

In the years following the Bavarian War, the League undertook several small-scale military operations while also serving as a forum for conflict resolution among its members. On average, the League handled five cases per year that involved disputes between allies. The frequency of these cases underscored the League’s importance as a mediator between neighbors, a role that smaller Estates found especially helpful. A majority of cases considered by the League involved disputes between Estates of differing stature, which meant that cities and the minor nobility used the League’s legal mechanisms as an added source of protection against encroachment from nearby princes. In 1506, for example, the League heard a dispute between the city of Nuremberg and the Margrave of Brandenburg-Ansbach-Kulmbach. Ten years later, it officiated a suit between the city of Augsburg and the local prince-bishop concerning control of a rural mill.Footnote ⁶⁶ Such cases represented a larger pattern where members sought legal resolution of disputes through League mediation rather than extrajudicial violence. The use of League arbitration to produce legally binding agreements continued a long-standing medieval practice where Estates employed leagues and other associations to settle conflicts with other authorities.Footnote ⁶⁷ By offering a forum for arbitration outside of standing institutions like the Chamber Court, the Swabian League followed in the footsteps of late medieval alliances and promoted many of the same goals. For all parties involved, the League provided a stable environment where each side could expect a fair and expeditious hearing. Its corporate structure facilitated this activity by placing Estates of differing status on an equal footing that imbued arbitration decisions with added weight. The leveling effect and collective identity promoted by alliances, therefore, proved crucial for their effectiveness as arbiters. As later chapters show, the resolution of conflicts among allies persisted as a hallmark of corporate alliances in both the Empire and Low Countries throughout the early modern period.

In part because of its success at resolving neighborly conflicts, League members renewed their alliance for another ten years in 1512. As in 1500, new members entered the League during the renewal process while others left. The most significant departure was Duke Ulrich of Württemberg. Ulrich had long desired to expand his territory by subjugating nearby cities in Swabia, but the membership of these cities in the Swabian League blocked Ulrich’s ambitions. The duke also chafed at the influence he believed Maximilian wielded over the League, and he complained about the “clear burdens” the alliance placed on him.Footnote ⁶⁸ In 1512, therefore, Ulrich withdrew from the League and formed his own alliance of princes as a counterweight.Footnote ⁶⁹ Ulrich’s counter-league proved less effective than the alliance he left, mainly because it lacked the cross-status consensus-building that marked the Swabian League. Nevertheless, tensions between Ulrich and League members escalated during the mid-1510s. They peaked in 1515–16 when Ulrich’s wife Sabina, the daughter of the now deceased Duke Albrecht IV of Bavaria, fled with her son Christoph from the abusive Ulrich out of fear for her life. She found exile in Bavaria with her brothers, dukes Wilhelm IV and Ludwig X, who had formed a power-sharing agreement to rule the duchy together. The fallout from the affair ultimately resulted in Maximilian imposing the imperial ban on Ulrich, which labeled Ulrich an outlaw in the Empire and threatened him with the loss of his title and territory. When negotiations to lift the ban failed, Ulrich and Maximilian appeared headed for war.Footnote ⁷⁰

Despite the ban’s imposition, Ulrich remained a powerful prince. The favor of King Francois I of France kept Ulrich supplied with enough funds to hire Swiss mercenaries, while Maximilian struggled to win allies to fight against him. Even the League hesitated. When pressed by Maximilian in 1517 to enforce the ban militarily, the League Council stated it would not act without a formal pronouncement against Ulrich from the Imperial Diet.Footnote ⁷¹ Maximilian tried to assure the League there was no need to wait, and that other Estates would follow its lead if it moved first. The only way to avoid “burdens and dangers for the Holy Empire and the League” was for the alliance to provide soldiers against Ulrich. League members should therefore act “not only as League allies, but as important members of the Empire.”Footnote ⁷² Maximilian drew a clear connection between the League’s activity and the health of the Empire, arguing that actions that benefited one would naturally profit the other as well. The dual loyalties that members had to the League and Empire were therefore complementary, which made it doubly important that the League move against a notorious opponent of the public peace like Ulrich.

Despite these imperial admonishments, the League Council remained noncommittal. Its members held true to their vision of the alliance as a supplement to the imperial organs of government and were unwilling to intervene without a clear mandate from those organs. Accordingly, Maximilian passed away in early January 1519 before he could marshal enough support within the League to move against Ulrich. The emperor’s death presented Ulrich with an opportunity to turn the tables. Wagering that the absence of a crowned emperor left the Imperial Diet and the Swabian League unable to counter him, Ulrich attacked League member Reutlingen on the pretext of avenging the death of a ducal official. The city quickly fell to Ulrich, but not before it appealed to the League Council for military assistance. The attack’s brazenness offered a clear test for the League’s willingness to defend its members, which assembled shortly after Reutlingen’s capture to discuss their reaction.Footnote ⁷³

Ulrich’s challenge to the League struck many as purposeful and strategic. A satirical song noted that Ulrich sought “to shut the League’s mouth” by showing that “the … League is not at all our equal.”Footnote ⁷⁴ This goal did not escape League members. Even before Ulrich’s attack on Reutlingen, League Estates had emphasized the need to stick together during the imperial interregnum to preserve the public peace in the absence of an emperor.Footnote ⁷⁵ The League now confronted a breach of that peace that held the potential to spark a larger conflict. The League therefore had to act. When the city of Esslingen announced that it had received a letter from Ulrich threatening military action against it as well, the League Council closed ranks and wrote a response that emphasized the League’s solidarity against Württemberg’s aggression.Footnote ⁷⁶ Leonhard von Eck, a leading counselor for the Bavarian dukes, pushed the League to go further. Eck saw Ulrich’s offensive as an opportunity to promote Bavarian interests, but he also recognized the wider danger that Ulrich’s actions presented to the imperial political system. Eck therefore advocated for the League to intervene militarily with the dual goal of expelling Ulrich from his territory and creating a regency government in Württemberg headed by the Bavarian dukes.Footnote ⁷⁷

Most Estates did not share Eck’s goal of strengthening Bavarian influence, but the majority of League members agreed that action was necessary. They therefore authorized the assemblage of a League army to expel Ulrich from Reutlingen in order to “implement the proper public peace as well as our alliance’s statutes.”Footnote ⁷⁸ This justification interwove protection of the imperial political system with defense of the League itself, much as Maximilian had done in 1517. It emphasized the symbiosis between the alliance’s operation and the Empire’s stability.Footnote ⁷⁹ This understanding was not restricted to League ranks. Popular chroniclers made the same connection, arguing in song that Ulrich merited condemnation since he “made war on the Empire.” Accordingly, its mission required that “the Swabian League [seek] vengeance against [Ulrich] with all its might.”Footnote ⁸⁰ Imperial and League interests fed off each other, and acting to protect one naturally benefited the other. This interconnectedness, which emerged during the 1504 Bavarian War and accelerated during the Württemberg crisis, established a precedent that for the next century and a half influenced how all subsequent leagues framed their relationship to the Empire. Far from showing the redundancy of the politics of alliance, the patterns established by the Swabian League convinced many Estates that corporate alliances formed an indispensable part of the Empire’s political system without which it could not fully function.

Despite the usual concerns about financing, the League’s 1519 military campaign proved successful.Footnote ⁸¹ At the end of February, more than 20,000 League troops crossed into Württemberg and captured Ulrich’s castles one after the other. By April, the entire duchy had fallen, and Ulrich fled into exile.Footnote ⁸² The League’s victory on the battlefield presented a new challenge. Now that the League controlled Württemberg, what should it do with it? This conundrum exposed rifts within the alliance. Some princes believed the war had primarily served the cities, since it occurred to protect urban members from Ulrich’s aggression. This fact shaped the wider perception of the war as well. One poet, for example, argued the war showed that the League’s princes should “not ally with cities, who’ll desert you in your need.” If princes continued to acquiesce to urban interests, then “the towns will flourish, [the princes] have but loss.”Footnote ⁸³ For their part, urban officials rejected this characterization out of hand.Footnote ⁸⁴ They pointed to the expedition’s high costs, which they claimed placed a greater burden on the cities than anyone else. They emphasized how League action benefited all members by reinforcing the alliance’s commitment to the public peace.Footnote ⁸⁵ Over the next decade, this divide between some princely and urban members, which echoed concerns voiced during the 1499 Swiss War, continued to grow. Eventually, it resulted in the League’s dissolution.

In 1519, however, League members found a solution all could bear. Most Estates rejected Eck’s plan for a Bavarian regency in Württemberg supported by the League, either because of the poor finances of the Württemberg government or because of fear that Eck might use the League for the personal aggrandizement of the Bavarian dukes.Footnote ⁸⁶ Divesting the territory to a third party looked like the best option, but the League demanded that anyone taking control of Württemberg reimburse the alliance for its war costs. This requirement left few viable negotiating partners outside of the new Emperor Charles V, who assumed office in June 1519. The situation became more urgent in August, when Ulrich launched a surprise attack to retake Württemberg.Footnote ⁸⁷ The League’s coffers, already drained from the February mobilization, could hardly bear a second military operation.Footnote ⁸⁸ If the League did nothing, however, Ulrich’s actions threatened to heap “damage, ridicule, and disadvantage” on the alliance, which would forfeit all the gains it had made in the spring campaign.Footnote ⁸⁹ As a way out, the League council proposed turning the duchy over to the emperor in exchange for “suitable payment of the war expenses.”Footnote ⁹⁰ It soon struck a deal. Charles V used his connections with the Fugger banking house to secure a loan to fund a new mobilization of League troops. Instead of paying the money back in kind, the loan terms established that the League could present Württemberg to the emperor as payment.Footnote ⁹¹

With the emperor’s backing, the League expelled Ulrich from Württemberg again. More than anything else, this second campaign convinced a majority of League Estates that keeping Württemberg in the League’s hands presented financial and military liabilities that could cripple the League’s ability to defend its member territories.Footnote ⁹² The cost of occupying the duchy was simply too high, while the danger of another attack from Ulrich followed by a budget-busting mobilization loomed ever present. Accordingly, in February 1520, one year after the initial invasion of Württemberg, the League Council struck another deal with Charles V. In exchange for handing Württemberg over to the emperor, the League received more than 200,000 Gulden in restitution for its costs and a release from all responsibility to defend the duchy in the future.Footnote ⁹³ This arrangement relieved the League of its immediate financial burden, and the imperial aide, Maximilian van Bergen, emphasized the deal’s value for both the League and emperor. In persuading Charles to accept the League’s terms, Bergen highlighted how the League “upholds law and order, and because of it all the powers of the Empire … must respect Your Royal Majesty more than they otherwise would do.”Footnote ⁹⁴ The League’s actions in Württemberg “made Your Royal Majesty into the Roman emperor. If [the League] had not acted, one can easily see how all your hereditary lands could have been lost.”Footnote ⁹⁵ The new emperor’s power and the security of his patrimony rested on the League. Only by cooperating with the corporate alliance could one realize the true promise of imperial governance.

Bergen’s statements spoke to a central truth of many corporate leagues. When successful, their operation benefited both their members and the imperial political system. For the Swabian League, this symbiosis peaked after the Württemberg operation. The mobilization to defend the public peace, the ability to defeat a powerful opponent through collective action, and its surrender of power and territory to the imperial crown represented all the values the League claimed to embody and its members hoped to uphold. At the same time, the Württemberg war showed the limits of the League’s military power. The high costs of mobilization and the realization that sustained occupation of Württemberg was not feasible showed the ad hoc nature of any military operation that the League undertook. This approach had clear advantages, and in Württemberg, it prevented the Bavarians from using the League as tool for their own ends. However, ad hoc arrangements meant that, if enough Estates viewed an endeavor skeptically, they could shut down military operations by refusing funding. As long as alliance members shared a common vision, this threat remained theoretical. Once this consensus evaporated, the military abilities of the Swabian League, like that of almost every successor alliance, stood on shaky ground.

Of Knights and Peasants

In the same year that the League transferred Württemberg to the Habsburgs, a Franconian knight named Hans Thomas von Absberg murdered a League prince, Count Joachim of Oettingen. Still recovering from the Württemberg operation, the League at first did little besides threaten retribution. Talk of a more substantive response surfaced during negotiations to extend the alliance in 1522, but League Estates renewed the alliance without committing to military action against Absberg. When a group of noblemen in Franconia proposed a knightly alliance to stand in solidarity with Absberg, however, the League Council could delay no longer. It ordered Absberg and his associates to appear before the League Court in an attempt to prevent their cooperation. When the knights appealed to imperial institutions for protection and condemned the League’s citation as a violation of the Empire’s constitution, the League launched a military campaign to subdue them. In the summer months of 1523, a League army laid waste to noble possessions in Franconia, destroying some twenty-three castles and shattering the knight’s proposed union. Absberg and many of his compatriots went into exile and launched sporadic raids against League territories for several years, but the League had achieved its goal. Its actions sent a clear message to any Estate that sought to defy it.Footnote ⁹⁶

The victory over the knights, combined with its suppression of a large-scale peasant revolt two years later, marked a high point for the League. Decisive, formidable, and merciless toward its enemies, the League’s defeat of knights and peasants in the mid-1520s put on full display the military might that it could unleash on less powerful foes. The lopsidedness of these triumphs, however, belied growing tensions within the League, especially between some of the alliance’s princes and many of its cities. Already during the debate over Württemberg, some princely officials had wondered whether the League did the princes any good, since it enabled “the prelates and cities” to undermine princely ambitions in a way that “the princes will not be able to tolerate or suffer for much longer.”Footnote ⁹⁷ Many urban magistrates offered the exact opposition characterization: that the League favored princely interests over urban ones. This dichotomy defined the final years of the League’s existence. As these divisions gradually became irreconcilable, the League also came into conflict with some of the Empire’s central organs of government. As a result, the 1520s witnessed some of the League’s greatest victories followed by a swift decline into paralysis and dissolution.

Absberg’s appeal to imperial institutions brought the League into competition with the Imperial Governing Council, an institution created in 1521 to act as a surrogate during the emperor’s absences from the Empire. Conceived of as a way to give Estates a greater say in imperial governance, the Governing Council relied heavily on officials from the Habsburg court. Charles also retained much of his authority despite the Council’s existence, so its actual abilities remained unclear.Footnote ⁹⁸ One area where the Governing Council did hold nominal jurisdiction was the enforcement of the public peace, although here it overlapped with the Swabian League’s sphere of activity. At the League’s 1522 renewal, Charles personally entrusted the alliance with “the implementation of our and the Empire’s established public peace.”Footnote ⁹⁹ This statement reaffirmed the League’s mission as enshrined in its charter dating back to 1488, but it also created uncertainty whether the League or the Governing Council held jurisdiction over breaches of the public peace that involved League members. This confusion broke into the open during the Knights’ War. Fearful of the League, Absberg appealed his case in late 1522 to the Governing Council, which asked the League to delay action until the legal case could work its way through imperial courts.Footnote ¹⁰⁰ The League Council pushed back, complaining that the Governing Council’s request equated to “cutting off the League’s hands.”Footnote ¹⁰¹ League Estates persuaded Charles’s brother Ferdinand, who led the Habsburg government in Württemberg and sat on the Governing Council, to support the League’s position. Ferdinand pressured the Governing Council to let the League enforce the public peace as it saw fit. The Council relented, and the League quashed the knights with little resistance.Footnote ¹⁰²

The ceding of authority in the Absberg case undermined the Governing Council’s legitimacy and drained much of its authority. This outcome corresponded with the wishes of several League princes, who saw the Governing Council as an affront to their “liberty” and sought to weaken it through the League.Footnote ¹⁰³ While more overt than many later instances, the competition between the League and Governing Council established a pattern of relationship between corporate alliances and some imperial organs of government that recurred in later decades. While alliances sought to supplement and strengthen imperial institutions, alliance members often saw their league as better able to protect the Empire than those same imperial institutions. This professed support for imperial organs of government while directly or indirectly sapping jurisdiction away from them defined the operation of numerous alliances through the end of the Thirty Years’ War. It shaped the process of state formation at the imperial level and within each alliance’s individual member states by bringing overlapping spheres of sovereignty into contact with each other and enabling league members to choose which option they believed best served the good of the Empire and their alliance at any given moment.

The League’s 1523 victory and the Governing Council’s delegitimization meant that a year later, when large-scale peasant revolts erupted across the Empire’s south, the League represented the only large entity connected to the imperial system that could intervene. One of the most studied revolts in early modern history, the German Peasants’ War, involved a series of related uprisings, stretching from late 1524 through 1526. Its supporters drew inspiration from past revolts as well as the new ideas of the Reformation, which gave it an explosiveness seldom seen before. The Swabian League played a key role in containing the uprising. As sporadic revolts cropped up during late 1524, League Estates at first resisted full-scale mobilization. While they perceived a threat to the alliance as a whole if separate revolts united together, many League members remained skeptical of incurring the costs of mobilization to subdue internal disturbances confined to individual territories. The League Council therefore tried negotiating with rebellious peasants, offering itself as a mediator between members and their subjects in the hopes of reestablishing order without the use of arms.Footnote ¹⁰⁴ This approach harkened back to previous League interventions in peasant-lord disputes and evoked a section in the League charter that offered subjects mediation through the League Council in case of a legitimate complaint against a member.Footnote ¹⁰⁵ As during the 1499 Swiss War, many League members viewed the early stages of the Peasants’ War as affecting individual Estates rather than imperiling the alliance’s collective interests.

This perception changed in early 1525, when it became clear that bands of rebels were uniting under common banners. In early February, as peasant armies massed in Swabia, the League issued a series of mandates ordering the rebels to disperse or face the League’s wrath.Footnote ¹⁰⁶ At just this moment, the League’s old nemesis Duke Ulrich resurfaced. On February 23, Ulrich marched troops into Württemberg in an attempt to use the uprising to retake his territory. Spirited debate ensued within the League about how to respond. While some princes argued the League should focus on the rebels, who presented the real danger, many urban magistrates emphasized the need to oppose Ulrich in order to prevent a wider disaster.Footnote ¹⁰⁷ As Ulrich Artzt of Augsburg put it, “if [the League] offers no resistance, then the peasants will join together with the duke.”Footnote ¹⁰⁸ Indeed, Ulrich struck a bargain with some peasant forces to support him, and he portrayed his invasion as an attempt to free his subjects from “tyrannical and unchristian” rule. Faced with such rhetoric, the majority of Estates saw Ulrich’s renewed aggression as a threat to the League’s stability, despite the fact that the League had no official duty to protect Württemberg under the 1520 terms of transfer to the Habsburgs. After much discussion, the League Diet approved the assemblage of an army to move against Ulrich in March 1525. As the two forces neared each other, Ulrich’s army disintegrated, and he withdrew from Württemberg for a third time in the face of a League army.Footnote ¹⁰⁹

The rebellious peasants remained. Surveying the situation in early spring 1525, one League official proclaimed that “the Devil is loose among the peasants. I have no idea how one will subdue them.”Footnote ¹¹⁰ The entire Empire stood on the precipice of destruction, stated the League Council in late March, and only the League could prevent disaster.Footnote ¹¹¹ Shortly after defeating Ulrich, therefore, the League declared the rebels violators of the public peace and enemies of the alliance.Footnote ¹¹² The time for negotiation had passed, but as requests for military aid poured into the League Council, some officials worried about the looming conflict’s cost. Urban representatives, who feared revolutions within their own walls as well as financial ruin from “a protracted war,” were especially concerned.Footnote ¹¹³ Overall, the League’s princes proved more enthusiastic about military action than the cities, where segments of the population sympathized with the rebels. Urban magistrates went along with the League’s plans, but they did so on their own terms, limiting how much money they fed into alliance coffers to fund the League army.Footnote ¹¹⁴ This decision underscored the cities’ importance to the League’s operation, a fact acknowledged by Leonhard von Eck, who noted that the only way to ensure victory over the peasants was “if some of the cities, especially Ulm, stand fast.”Footnote ¹¹⁵ Urban reluctance to offer full financial support meant about two-thirds of the operational costs fell on the princes, a situation that upended the usual arrangement where princes led and cities paid for the army. The greater monetary investment of the princes strained their finances, but it also diminished the influence cities could exert over League policy during the war.Footnote ¹¹⁶ The ensuing campaign was brutal, resulting in the death of thousands of peasants, the execution of numerous rebel leaders, and the temporary occupation of several cities suspected of aiding the rebels.Footnote ¹¹⁷ The distrust that the war stoked weakened the alliance’s unity and hastened it toward a full internal crisis.

Despite these challenges, the Swabian League held together in 1525 for one last great military undertaking. Its cross-status, interregional composition meant the League was the only entity capable of defeating the peasant armies scattered across southern Germany. Its members recognized this fact.Footnote ¹¹⁸ In its official justification for moving against the peasants, the League Council emphasized its responsibility as a corporate alliance sanctioned by the emperor to intervene “for the preservation of each Estate’s authority and lordship in the Roman Empire.” The notion that the League’s actions benefited not only its members but also “the entirety of Germany” dominated the League’s defense. It found a receptive audience with imperial officials, who noted that without the Swabian League, “the entire Roman Empire of the German Nation would have been lost.”Footnote ¹¹⁹ One contemporary songwriter put it more poetically, arguing that the League’s actions in the war “ennoble the Roman Empire and punish evil deeds, just as God has ordained.”Footnote ¹²⁰ In many areas during the Peasants’ War, the Swabian League became the physical embodiment of the Empire. Peter Blickle has gone so far as to argue that during the chaos of the war, the League’s army developed into “a halfway functioning imperial institution.”Footnote ¹²¹ By the end of summer 1525, this quasi-arm of the Empire had quashed the peasant revolts in its member territories and begun a program of repression against the surviving rebels that reverberated through the alliance’s final years.

In one sense, the Peasants’ War saw the Swabian League at a height of power, as its victory reaffirmed its centrality to the Empire’s political system, especially during times of uncertainty. As Peter Blickle has argued, the war showed that “during the 1520s, no imperial institution functioned better than [the Swabian League] did.”Footnote ¹²² Its actions confirmed the importance of corporate alliance for the Empire, which relied on the politics of alliance to put its ideals into practice in many of its regions. The Empire needed the League’s support to thrive, while the League drew legitimacy from its devotion to serving the Empire. Both depended upon each other, and their symbiosis framed the development of their member states.

At the same time, the war exposed growing divisions in the League that hinted at troubles on the horizon. Many princes blamed urban magistrates for the war, arguing “that the peasant insurrection mostly has its roots in the cities.” Urban leaders naturally rejected these accusations, which exacerbated growing urban-princely antagonism in the alliance. Moreover, as the Bavarian aide Leonhard von Eck noted, the revolt also divided the cities. In a candid letter written in early March 1525, Eck observed that among the League’s cities “there is a great split: the poor Lutherans side with the peasants, while the non-Lutherans and rich Lutherans are against the peasants.”Footnote ¹²³ Internal religious dynamics were pushing certain cities away from the princes and even from other communes. This erosion of common ground brought the League to its knees in the aftermath of the war’s carnage. One of the Swabian League’s greatest successes carried with it the seeds of its eventual dissolution.

The Reformation and the League’s Twilight

As Eck observed, the largest variable introduced into the League’s internal dynamics during the 1520s was the Reformation. Calls for religious reform swept across the German lands in the late 1510s and early 1520s. Advocates of reform attacked the Catholic Church as financially and theologically corrupt. They decried what they saw as outward displays of false piety such as indulgences that profited the Church’s bottom line. With the goal of restoring the purity of Christian worship, reformers rejected the authority of Rome and preached the cultivation of a spirituality focused on the individual believer’s faith in God. Scripture alone as the basis of Christian truth, rather than reliance on Church tradition, became a widespread rallying cry in all kinds of communities. This emphasis on Scripture as the sole basis for Christian practice led reformers to call for the abolition of the Catholic Latin Mass and the establishment of Church services in the vernacular, among many other liturgical changes.

Scores of reformers – some inspired by Martin Luther’s ideas, some preaching their own visions for Christian renewal – appeared across the Empire in the 1520s. Labeling themselves and their followers as Evangelicals after the Greek name for the Gospels, they found receptive audiences with commoners and political authorities alike. The popularity of reform ideas made them difficult to suppress. In 1521, Emperor Charles V tried to halt the spread of reform with a decree known as the Edict of Worms. The Edict prohibited the publication and preaching of Lutheran ideas while placing Luther under the imperial ban. It met with limited success. While some officials tried to institute the Edict in their territories, most Estates largely ignored it. They did so partly out of sympathy for the nascent reform movement and partly out of fear of the social upheaval that could result if they attempted to suppress calls for reform.Footnote ¹²⁴ That individual Estates could turn a blind eye to the emperor’s decree highlighted the perpetual challenge faced by imperial organs of government in turning their prerogatives into action at the local and regional levels. The Reformation heightened these problems, which created an opportunity for corporate alliances to act, if they could find a way to neutralize or coopt the religious question.

The willingness to disregard the Edict of Worms was especially strong in cities, which provided the home base for many reformers and contained a critical mass of people attracted to their ideas. A few cities, such as Nuremberg in 1525, officially broke with Rome, cut their ties to the local bishop, and introduced a council-led reformation of their churches. During the 1520s, however, the majority of cities adopted a policy of accommodation, allowing reform preachers to operate within their walls while not officially outlawing the Latin Mass or jettisoning their relationship to Rome. In so doing, they hoped to head off the potential for social revolution fueled by religious concerns. For their part, some League princes embraced religious reform, most notably Landgrave Philipp of Hesse, but most League princes opposed the Reformation as heretical and blamed it for the Peasants’ War. Many advocated programs of repression within their territories. These diverging religious convictions put League Estates on opposing paths that ultimately crippled their ability to act collectively.

League Estates did manage to find some common ground on religious reform, most notably a 1528 agreement to persecute supporters of a radical religious movement known as Anabaptism. For the most part, however, the Reformation solidified the rifts in the alliance that had grown since the Württemberg expedition. Acting on their conviction that urban flirtations with heretical ideas had provoked the Peasants’ War, many League princes tried to use the League as a legal and military tool to combat the spread of religious reform. In the aftermath of the Peasants’ War, the League Council issued articles of complaint against the behavior of some urban members.Footnote ¹²⁵ These actions culminated in July 1527, when a group of princes pushed a resolution through the League Council demanding that League cities expel all “ringleaders” of the Peasants’ War from their midst. The mandate also ordered urban leaders to kick out any clergy who had left the Catholic Church for the new faith.Footnote ¹²⁶ A year and a half later in January 1529, the League Council escalated its legal struggle against religious reform when it sought to expel Hans Keller, representative of the city of Memmingen, in retaliation for the city’s decision to outlaw the Latin Mass.Footnote ¹²⁷ Both instances marked attempts by Catholic princes to employ the League’s apparatus as a legal battering ram against the Reformation and those urban magistrates that seemed intent on fostering heresy and disorder.

The League’s urban members recognized the gravity of the situation. Their response shaped how corporate alliances conceptualized the place of religion within their structures for years to come. Seeing the 1527 mandate as a direct attack on urban independence, the League’s cities closed rank to protect their collective interests. They disputed the League’s legal jurisdiction in matters of religious reform, arguing that the alliance “applies only to external matters and not at all to affairs that touch the faith, conscience, and soul of men.” The League’s mandate violated the alliance’s basic principles, since its enforcement would not preserve the public peace. Rather, it would lead to “the shedding of blood, certain revolt and uprising, as well as the loss and destruction of all good order and governance.”Footnote ¹²⁸ Instead, the League should respect the decision of the 1526 Imperial Diet of Speyer, which declared that each Estate remained free to organize religious practice within its jurisdiction “in such a way as can be justified to God and the emperor.”Footnote ¹²⁹ In the eyes of these urban magistrates, the League had overstepped its legal authority, as it possessed no right to regulate the religious convictions of its members or their subjects. Rather, League activity needed to reorient toward its true purpose: preserving the peace and supplementing the imperial organs of government.

Similar claims met the 1529 attempt to expel Keller from the League Council. Many urban leaders again denied the Swabian League any legal authority to intervene in the internal religious affairs of its members.Footnote ¹³⁰ The scheme to remove a duly appointed Council representative also cut to the heart of the alliance’s role as a mediator between Estates of differing status. In characteristically dramatic fashion, Ulm’s magistrates highlighted the stakes. If the League’s urban members did not assert their independence to counter the prince’s actions, “there will be no other result than that the League’s cities, alongside all their onerous burdens, will be subjugated to the other Estates and become their slaves and bondsmen.”Footnote ¹³¹ Such fears, flamed to new heights by divergent religious convictions flowing from the Reformation, proved deadly for the ability of Estates to cooperate in the League. As Nuremberg’s city secretary, Lazarus Spengler, observed after the Keller Affair, “many in the League have no greater enemy right now than the Gospel.”Footnote ¹³² In order to preserve true Christian worship, one had to curtail the League’s legal jurisdiction. Ulm’s magistrates even pointed to the Keller Affair as a reason to reject the League’s renewal, since it showed that many League members were more intent “on persecuting the cities because of their faith than protecting them from wrongful attacks.”Footnote ¹³³ The spread of reform ideas accelerated an existential crisis in the League that led its urban members to question the basic value of League membership.

In a fateful move for the Empire’s history, the urban arguments carried the day. In both 1527 and 1529, the cities successfully rebuffed the attempt of League princes to impose anti-reform policies on them. Their effort to remove religion from the League’s jurisdiction marked a legal innovation that reappeared in numerous alliances over the next two centuries. It even carried the seeds of later Empire-wide arrangements that reshaped the authority of Estates to organize religious practice within their jurisdictions. In the late 1520s, it accelerated an erosion of trust that led League members on all sides of the religious dispute to question whether the League still served their common interests. This growing distrust found clear expression in the Pack Affair. In January 1528, several documents fell into the hands of League member and reform adherent Landgrave Philipp of Hesse that detailed the creation of a secret alliance among Catholic princes to eliminate the Reformation through force. Philipp responded by organizing a military pact with other reform-minded princes in order to launch a preemptive war against the Catholic conspirators. At the last minute, it came to light that a Saxon official named Otto von Pack had fabricated the dossier, and no such Catholic alliance existed. Tensions deescalated, but not before Philipp had raised an army and used it against several bishoprics in Franconia that also belonged to the Swabian League.Footnote ¹³⁴

Philipp’s attack on fellow League members ensured that the Pack Affair left scars in the alliance.Footnote ¹³⁵ Many Catholics accused their allies of using the fabricated conspiracy as an excuse to invade Catholic territories. They leveled this allegation in fierce tones against several League cities, most notably Nuremberg, which many princes suspected of funneling money to Philipp.Footnote ¹³⁶ Citing a secret meeting that Philipp held with city officials, some League members even accused Nuremberg of being “the start and cause of this disturbance.”Footnote ¹³⁷ Nuremberg’s magistrates denied any wrong-doing, but the damage had been done. In May 1528, when the League Council called for a special mobilization against Philipp, some of the alliance’s reform-minded cities hesitated to approve their portion of the funding. Not surprisingly, Nuremberg proved especially skeptical. Since Catholic princes led the call for mobilization, Nuremberg’s magistrates feared that bankrolling armies to attack another Evangelical would mean “offering aid against the Gospel, its helpers, and adherents. That is, to offer aid against oneself.” Such an act would undermine the entire purpose of belonging to the alliance.Footnote ¹³⁸ The religious convictions of Nuremberg’s magistrates, therefore, led them to question the viability of the Swabian League, since the divergence of interests brought on by the Reformation meant that the responsibilities of League membership might force one to act against one’s conscience. The only solution to this dilemma was for the cities to withhold funds for the mobilization as “a means … of open protest.”Footnote ¹³⁹ Similar arguments echoed through alliances for generations to come.

Some League cities pushed back against Nuremberg’s proposal. They argued that League members had no right to withhold funds for military action if the full League voted for it. Nevertheless, Nuremberg persisted. In the process, it crystallized a view of how military decisions should occur within alliances that became a staple of urban politics of alliance. Nuremberg’s council emphasized that League cities should not act against their self-interest just because allied Estates asked them to do so. If the cities let the princes dictate the terms of military action, then the League became nothing more than “a game of dice” whose outcome the cities could not foresee.Footnote ¹⁴⁰ By refusing funding, the cities could set the terms of debate and ensure the best possible result. When viewed in concert with Ulm’s comment from a few months later about the cities becoming the princes’ “slaves and bondsmen,” the extent to which relations among many League cities and the alliance’s Catholic princes had soured comes into full relief. The Pack Affair ultimately faded away once the false nature of Pack’s documents became clear, but accusations that certain cities had plotted against the League continued to swirl for months, creating part of the context for the 1529 attempt to remove Keller.Footnote ¹⁴¹

The Pack Affair, alongside the other religiously driven controversies, indicated that the League and the politics of alliance writ large were entering a new phase dominated by the religious divisions gripping the Empire. The aftermath of these controversies signaled the beginning of the end for the Swabian League. Ulm’s council summed up the central problem when it observed that any “evangelical city can expect little help from their ecclesiastical and papist League allies … For just as it troubles the conscience of evangelical cities to come to the aid of the ecclesiasts and papists in preserving the papal religion, so too it troubles the ecclesiasts to help the evangelical cities, which they call Lutheran and Zwinglian and whose faith they label a heresy.”Footnote ¹⁴² This erosion of trust and common purpose proved fatal. As the League attempted to hold together in the wake of the Pack and Keller affairs, Emperor Charles V assembled an Imperial Diet at Augsburg in 1530. Promising to settle the Empire’s religious divisions, Charles ordered reform supporters to submit a formal statement of their beliefs for consideration. On June 25, a contingent of theologians led by Luther’s close associate Philipp Melanchthon presented the Augsburg Confession, a creed that laid out the fundamental principles of Lutheran thought in twenty-eight articles. It became the foundational document of Lutheran doctrine. A few weeks later, four southern cities – Constance, Lindau, Memmingen, and Strasbourg – submitted their own Four-Cities Confession, or Tetrapolitana, which inclined toward the emerging Zwinglian-influenced Upper German school of reform. Charles gave his theologians several weeks to respond. On August 3, he issued his Confutation, which rejected the Augsburg Confession. In October, his theologians refuted the Four-Cities Confession as well. When the diet recessed in November, the emperor persuaded a majority of Estates to reaffirm the Edict of Worms and to mandate that all Estates comply with its requirements by April 1531.

For the Swabian League, the Diet of Augsburg brought a reckoning. League members faced a stark choice: follow the emperor’s directive and remain in the League, or preserve the Reformation within their territory through new corporate protections. Rejecting the emperor’s demands, several evangelical League members, including Philipp of Hesse and Ulm, broke from the Swabian League in 1531 to form a new alliance to defend the two reform confessions submitted in Augsburg. Known as the Schmalkaldic League, the next two chapters narrate its fate. At the same time, within the Swabian League, Protestant princes joined the cities in denying the League’s ability to intervene in religious affairs. In November 1532, Ulm’s council flat out refused to aid any bishop that sought assistance suppressing the Reformation, and other Estates followed suit.Footnote ¹⁴³ This evangelical front attacked the very basis of the alliance: the idea of majority rule through the League Council.Footnote ¹⁴⁴ Adherents of the new faith would not surrender their religious beliefs for the League, but instead sought to create new bonds of alliance to preserve their faith. As Philipp argued in January 1533, “the League holds back the Gospel in many ways and is more than a little burdensome for those that adhere to the Gospel.”Footnote ¹⁴⁵ In this environment, negotiations to renew the League had little chance of success, especially given the desire of Ferdinand and Charles V to make the League a bastion of Catholic opposition to the Reformation. In February 1534, the Swabian League dissolved after forty-six years of operation. The power vacuum it left behind, and the bewildering array of alliances that sought to fill it, transformed the Empire’s political system over the next two decades.

Conclusion

During the first three decades of the sixteenth century, the Swabian League’s collective resources enabled it to become one of the most effective fighting forces of its time. The League was not a formal standing institution like the imperial diet or Governing Council, and its self-imposed limitations restricted its sphere of activity. Nevertheless, the League’s cross-status nature, its ability to alter its structure periodically, and its close intertwining with the imperial political system fostered a dynamism that sat at the core of the League’s appeal. During its heyday, the League operated as the most visible embodiment of the ideals of public peace and collaborative action that many Estates saw as the basis of the Empire’s constitution. At several points during the early sixteenth century, especially in the 1520s, the League functioned better than some imperial institutions and reacted more swiftly in moments of crisis than any of them could. Its achievements established the League as the standard against which all later alliances would be judged. Its activity also set up patterns that repeated time and again in future leagues. In the process, the Swabian League not only directly influenced the development of numerous individual states, such as Württemberg, Bavaria, and a slew of cities and knightly territories. It also generated impulses that provided part of the framework within which the broader process of state formation in the Empire occurred for generations.

While the League’s structure facilitated its many successes, it also eventually led to its demise. Paradoxically, as the League sat at the height of power in 1519–25, it began to come apart at the seams. The religious split among its members proved too much to overcome, as it exacerbated wrangling over the financing of military operations and eroded a sense of common purpose within the League. A conviction that the League served the interests of all its members bound it together. The Reformation made this ideal difficult to maintain, especially after the Peasants’ War. The latent urban-princely rivalry within the alliance devolved into open conflict, as numerous members, including some princes like Philipp of Hesse, took up religious reform. When Estates began to deny the League’s authority in matters of religion, its end came as members resisted League attempts to exert its shared sovereignty to combat the Reformation.

The influence of religious divisions on the League’s downfall was not lost on contemporaries. When the League officially dissolved on February 3, 1534, a Catholic monk named Clemens Sender in the member city of Augsburg lamented that “the praiseworthy Swabian League” had come to an end “against the wishes and order of His Imperial Majesty.” It had disbanded, claimed Sender, “solely because of differences in matters of Christian belief, so that the Zwinglians and the Lutherans can persist in their errors.” Sender followed up this partisan Catholic appraisal with an observation that League members of all religious persuasions might have echoed: “While the Swabian League had an honorable beginning, here it came to an ignoble conclusion and ending.”Footnote ¹⁴⁶ This bad end found its clearest expression a few months after the League’s dissolution, when Duke Ulrich finally succeeded in reconquering Württemberg. Assisting Ulrich in his return to power was Philipp of Hesse, who led a new corporate alliance designed to defend the Reformation, the Schmalkaldic League. The days of the Swabian League were over. As we shall see, however, while it may have met an “ignoble ending,” the Swabian League would never be forgotten.