One hundred years ago, a group of Episcopalians – the Franciscan Friars and Sisters of the Atonement – led by Fr. Paul Thomas Wattson and Sr. Mary Lurana White in Garrison, New York at Graymoors, started the observance of a week of prayer for Christian unity. The whole story is fascinating and encouraging since it traces the emergence of ecumenism in the 20th century. Fr. Wattson and the Franciscan Order of Atonement, which he co-founded, entered the Catholic Church in 1909 but continued to promote Christian Unity.

During the 1920s and 30s there was a growing movement for Christians to observe a week of prayer for Christian unity. During the Second Vatican Council (1962-1965), interfaith dialogue and prayer received a new emphasis with the 1964 issue of the Decree on Ecumenism, which called prayer the core of the ecumenical effort and encouraged Catholics to observe a week of prayer. In 1966, the Faith and Order Commission of the World Council of Churches and the Vatican Secretariat for Christian Unity began working on a common set of prayers for the Octave. Since 1968, The Graymoor Ecumenical and Interreligious Institute has facilitated and published the international texts for use in the United States. In 1991, a Sunday was incorporated into the week of prayer. Each year’s theme is developed by an ecumenical group whose members are appointed by the World Council of Churches and the Pontifical (Catholic) Council on Ecumenism. The 2008 theme is “Pray without ceasing” (1 Thes. 5-17).