The Walloon Movement was a left wing movement from its beginning. Started in liberal left societies, it quickly became a rallying cry for a liberal-socialist coalition against the conservatives of the Catholic Party whose power base was in the Flemish-speaking provinces. During the interbellum between World War I and World War II, many of the Christian left joined the Walloon Movement, notably the Abbé Mahieu, an anticlerical Catholic priest. The movement was the focus of several attempts to create left-wing party, for example the Walloon Democratic and Socialist Rally (Rassemblement démocratique et socialiste wallon) created during World War II.