The Second Wave of Western European Left Catholicism, c. 1965 – c. 1975, introduced manifold innovations in comparison to the First Wave, c. 1944 – c. 1954, in addition to reinforcing older traditions, such as the phenomenon of worker priests, which had served as the most visible and symbolic marker of progressive Catholicism in the immediate postwar era. Of the organizational novelties leaving their mark on the post-Vatican II era, it is probably fair to say that the emergence and powerful presence of radical priest associations, above all the Christian Solidarity International Congress, and the rise of spontaneous ecclesial communities, eventually best known by the term ‘base communities’, were the principal innovations. In addition, the specifically Catholic contribution to the European (and worldwide) student movements, as well as the specifically Catholic impetus behind radical working class practices in the Long Sixties were likewise unprecedented phenomena. There had been Catholic agitators in workers’ movements in the immediate postwar era, but such actions took a different form compared to Catholic working class activism in the Long Sixties, the latter period witnessing radical activity organized by Catholic trade unions, a feature with no parallel twenty years earlier. The rise of progressive, system-challenging radical student movements as such, not just the specifically Catholic battalions within those currents, was of course also a phenomenon entirely without precedent in European history. [First paragraph]