In what Horton Davies described as ‘the ecumenical century’ the most decisive steps were taken in the twenty-five years after 1945. The inauguration of the World Council of Churches in 1948 brought together the major Protestant churches, the Ecumenical patriarchate, the Church of Greece and Orthodox churches in North America; in 1961 the Russian Orthodox church and other Orthodox churches from ‘Iron Curtain’ countries joined. The Roman Catholic church had remained outside that movement between the wars, with the papacy holding that schismatic churches should return to the mother church. However, the election of John XXIII in 1958, the establishment of the Secretariat for Promoting Christian Unity in 1960 and the Second Vatican Council (1962–5) substantially changed relationships between the Roman Catholic church and other churches. Like his predecessor, Pope Paul VI met with other church leaders; the mutual anathemas of 1054 between East and West were revoked, and a similar agreement was reached with the Coptic church.

It proved easier to bring churches together in organisations where their individual identity was not lost than to inaugurate structural reunion. Thus the pace of ecumenical advance seemed to slacken in the last quarter of the century.

Edinburgh 1910

The World Missionary Conference held at Edinburgh in June 1910 is regarded as the starting point of the modern ecumenical movement. From this are traced the people and institutions that became characteristic of twentieth century ecumenism.