Ideological and political movement of the late nineteenth and twentieth centuries. It arose at the seat of Catholicism, stemming from Pope Leo XIII’s famous 1891 encyclical Rerum Novarum (although at the beginning of the twentieth century the ecclesiastical hierarchy preferred to use the term “Christian Socialism” or social-Christianity). Only in the course of the struggle against fascism, especially during and after the Second World War, did the Holy See put its seal of approval on official use of the term “C.D.”, allowing its supporters to unite politically and form Christian Democrat parties in many countries of Europe and Latin America, and subsequently in some countries of Africa and Asia. In the 1950s these parties affiliated in the Christian Democrat International. These parties came to power in many countries including Germany, Italy, Chile, Costa Rica, Panama, Venezuela, and other countries of both Europe and the Americas. The collapse of the Christian Democrat party in Italy in the early 1990s seriously accentuated the crisis in the Christian Democratic movement. The theoretical basis of C.D. rests on the social doctrine of the Catholic Church and on ecumenicalism, which allows the C.D. movement to extend its influence into those sectors of the population that adhere to Protestantism in its various manifestations. The philosophical work of the French neo-Thomist philosopher Jacques Maritain, especially his doctrine of integral humanism (*Christian Humanism, have exerted great influence on the political concepts of C.D.