The lesson of the Popish Plot, that the law was almost powerless against perjury, was widely applied in political accusations, administrative disputes and criminal prosecutions, particularly in the 1690s when so many former Exclusionists were in office or Parliament. MPs such as John Arnold, who had employed suborned evidence against the Monmouthshire Jesuits in attempting to overthrow the pro-Catholic Marcher magnate, the Duke of Beaufort, found it too good a weapon not to use in every-day politics. The Catholics, however, were not the main sufferers; the destruction of their Court party at the Revolution made them comparatively insignificant. Oates's successors, remembering the impunity with which he had attacked the Queen, James and Danby, laid their charges of treason against ministers or opposition leaders. However, one late offshoot of the Plot has caused some difficulties in Catholic history; it is another reminder that the compilers of the official records combined ignorance with their anti-Catholicism, holding with one judge during the Plot, that ‘They have such secret contrivances among themselves … that where there are two men that positively tell you a thing that lies within their knowledge and swear it is true, it is scarce any improbability that should weigh against such an evidence’. Land or money given to ‘superstitious’ uses was legally forfeit to the Crown under the Chantries Act (1 Edw. VI, c.14), extended (by implication) to the support of foundations abroad under 27 Eliz., c.2, sect. 4 The official findings in this decade are so odd that usually they have wisely been ignored; yet local historians can be deceived or confused. This investigation provides a full explanation and a glimpse of the Catholic underworld on which anti-Catholicism largely depended.