Free movement of labour was established as a so-called principle, that is, one of the four fundamental norms governing all community policy, in the Treaties of Rome in 1957. Yet already from this beginning, what was to be understood as labour, and what was not, was up for debate. In due course, judicial disputes would arrive at the European Court of Justice in Luxembourg, most of them related to migration. While claims to social security benefits by Italian miners played the most important part in the first couple of years following the Treaties of Rome, over the course of the decades a vast variety of welfare and social policy issues came to be associated with free movement of labour. As time went on, the trajectory pointed to a broader, both more complex and more flexible understanding of what constituted labour as the number of cases brought to Luxemburg increased that dealt with activities previously not regarded as work. Students and sex workers, unemployed and sick persons were demanding national benefits through European channels, transcending the boundaries of national welfare state systems and helping re-define labour and work in the process. This article will chart this development by studying a sample of cases that arose in Belgium from 1972 to 1988, tracing the social transformations that gave rise to the legal claims and analysing how these were translated into the language of Community law and endorsed or rejected by the Court.