In Rome, in May 1961, on the occasion of the 70th anniversary of the encyclical “Rerum Novarum”, delegates from 42 movements decided to create a worldwide movement of Christian workers. This creation is part of a world in turmoil after the Second World War. It also comes after many exchanges and debates between the founding movements. The obstacles were many related to the history of countries and churches, languages, and movements themselves. But the WMCW birth was made possible thanks to the willingness of each movement to open up to others, to accept differences as a richness in order to open up to the universal and to make cultures dialogue in  common project that goes beyond national interests. This creation of an international movement is part of the context of the Vatican Council II, which gives the Catholic Church a great breath of renewal and hope.