International Week of Prayer for Christian Unity

The Week of Prayer for Christian Unity is an international Christian ecumenical observance kept annually between 18 January and 25 January. It is actually an octave, that is, an observance lasting eight days.

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, cofounder of the Graymoor Franciscan Friars. He conceived of the week beginning on the Feast of the Confession of Peter, the Protestant variant of the ancient Feast of the Chair of Saint Peter, on 18 January, and concluding with the Feast of the Conversion of Saint Paul on 25 January.

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 Christian unity and the Petrine See (i.e., the papacy).

Protestant leaders in the mid-1920s also proposed an annual octave of prayer for unity amongst Christians, leading up to Pentecost Sunday (the traditional commemoration of the establishment of the Church). (source: wikipedia.com)

Theme for 2015:
Jesus said to her: "Give me to drink"
(John 4:7)