The Week of Prayer for Christian Unity is an ecumenical Christian observance in the Christian calendar that is celebrated internationally. It is kept annually between Ascension Day and Pentecost in the Southern Hemisphere and between 18 January and 25 January in the Northern Hemisphere. It is an octave, that is, an observance lasting eight days. The Week of Prayer for Christian Unity is annually coordinated by the World Council of Churches, with participation by its member Churches, which include the Assyrian Church of the East, the Oriental Orthodox Churches, the Eastern Orthodox Churches, the Old Catholic Church, the Moravian Church, the Lutheran Churches, the Anglican Communion, the Mennonite Churches, the Methodist Churches and the Reformed Churches, as well as the Baptist Churches and the Pentecostal Churches. The Roman Catholic Church, which is an observer in the World Council of Churches, also celebrates the Week of Prayer for Christian Unity. Beginnings The Week of Prayer for Christian Unity began in 1908 as the Octave of Christian Unity, and focused on prayer for church unity. The dates of the week were proposed by Father Paul Wattson, co-founder of the Graymoor Franciscan Friars. He conceived of the week beginning with the Feast of the Chair of Saint Peter, which was then kept on the General Roman Calendar on January 18 - the same day that the Anglican Church kept the Feast of the Confession of Saint Peter - and concluding with the Feast of the Conversion of Saint Paul on January 25. In 1960 Pope John XXIII removed from the General Roman Calendar the January 18th feast of the Chair of Peter, along with seven other feast days that were second feasts of a single saint or mystery and merged it with the Feast of the Chair of St. Peter at Antioch, kept on February 22. This calendar was incorporated in the 1962 Roman Missal. Hence, only those Catholics who still retain the General Roman Calendar of 1954 keep the January 18th Feast, although the date continued to serve as the beginning for the Unity Octave. The Feast of the Confession of Peter continues to be observed by Anglican churches on January 18. Pope Pius X officially blessed the concept, and Benedict XV "encouraged its observance throughout the entire Roman Catholic Church." For a while, the observance was renamed the "Chair of Unity Octave" by Wattson, in order to emphasize the relationship between