The word "ecumenism" comes from the Greek "oikuoméne", meaning the (inhabited) earth. It is a practical orientation which aims to create an ongoing interaction and fellowship between the various Christian churches. The Reformed churches propose a vision of Christian unity which desires to return to the communion in diversity which was characteristic in the New Testament. The Greek term "koinonia" is often used for this kind of communion. The Protestant conception of unity is at the origin of the ecumenical movement, the most important of its structures being set up after the second half of the 19th century. In 1875 the Alliance of Reformed and Presbyterian churches was founded, followed by the Methodist World Council in 1881, the Baptist World Alliance in 1905 and the Lutheran World Federation in 1929.
Parallel to these confessional structures, attempts to achieve interdenominational collaboration were made. The first of these was the Evangelical Alliance, created in London in 1846 by an assembly of 900 Christian members of 52 different Protestant churches, coming from all over the world. A missionary conference, uniting representatives of all the Protestant denominations, of the Anglican churches and Old Catholic churches for the first time, was held in Edinburgh in 1910. This conference can be considered to be the true start of the ecumenical movement. From its beginnings, the movement has had two strands or orientations: the theological (unity of faith) and practical (unity in action). The first strand is related to the Faith and Order movement, inspired by American Bishop Charles H: Brent of the Episcopal church (1862-1929), while the inspiration and initiative of the Swedish Lutheran Bishop, Nathan Sòderblom (1866-1931), led to the Life and Work strand. Both these movements, which came into being after the Edinburgh conference, led to the first great World Ecumenical Assemblies. The most important of these were the Stockholm Assembly of 1925 and the Lausanne Assembly of 1927. The two movements joined to become the Ecumenical Council of Churches in 1948. The most important ecumenical assembly of recent years is undoubtedly that of Lima (Peru) in 1982, which clearly defined the three "convergence documents" on baptism, eucharist and ministry issues.