The Jesuit and palaeontologist Pierre Teilhard de Chardin is basically known for his not always orthodox conceptions by which lie tried to reconcile evolutionist science with his personal spiritual ideas. In spite of censorship from the ecclesiastical authorities, Teilhard attempted to elaborate this conciliation and to spread it among catholic intellectuals. For both of these projects he found crucial support in evolutionist circles at the Catholic University of Louvain and the Jesuit house in the same Belgian town. Teilhard's Louvain network proved to be an important sounding board and it offered concrete help in spreading his ideas and in bypassing the censorship. Despite significant mutual influences, philosophical divergences between Teilhard and his Louvain friends remained, and would eventually drive them apart. Therefore, in the 1930s, Teilhard's Louvain network largely dissolved. However, its actions had not been without result. This small group of intellectuals definitely changed the climate among Catholics in favour of evolutionism and thus prepared the success that Teilhardian ideas would have in the aftermath of the Second World War.