Ecumenism refers to efforts among Christians to improve dialogue and reduce divisions among different denominations and churches with the goal of forging Christian unity. Divisions in doctrine and practice have historically characterized Christianity and relations among its three major branches, Orthodox, Roman Catholic, and Protestant. For more than a century Christian leaders have sought to reduce their differences across a wide range of issues, including the person of Jesus Christ, the meaning of his death and resurrection, and the number and significance of the different sacraments, particularly baptism and the Lord's supper. Other key issues have included church structures—for example, the authority of the pope and the bishops—and relations with Jewish and other non-Christians communities.
During the twentieth century, Protestants took the lead in founding the ecumenical movement. The World Council of Churches, founded in 1948, was an institutional embodiment of the spirit of dialogue. The Roman Catholic Church resisted the idea of ecumenism until the Second Vatican Council (1962-1965), when it relaxed its historical view that non-Catholics were not true Christians. Like the Eastern Orthodox Church, it participates in ecumenical discussions while insisting that it most perfectly embodies the continuity of the Christian tradition. Despite significant progress, such as a joint statement by Catholic and Lutheran theologians on the controversial topic of justification, fundamental differences within and across the three main branches of Christianity remains. Over the past two decades they have been exacerbated by disagreements over the status of women in the church and the LGBTQ community.