The traditional date for the Week of Prayer for Christian Unity
is 18-25 January. These dates were proposed in 1908 by Paul Watson 
to cover the days between the feast of St. Peter and the feast of 
St. Paul, and therefore have a symbolic meaning. In the southern 
hemisphere where January is a vacation time churches often find other 
days to celebrate the week of prayer, for example around Pentecost 
(which was suggested by the Faith and Order movement in 1926), which 
is also a symbolic date for the unity of the church).

From 1926 onwards, the Faith and Order movement published suggestions
and guidelines for an "Octave of Prayer for Christian Unity" to be
celebrated at Pentecost. Then in 1935, Paul Irenee Couturier, a French
priest who devoted much of his life to working for Christian unity, 
was instrumental in establishing a 'Universal Week of Prayer for Unity'.

Subsequently, from about 1957, an agreed theme and appropriate materials
to be used during the Week of Prayer for Christian Unity were prepared
through informal co-operation between the World Council of Churches'
Faith and Order Commission and the Roman Catholic Church's Unite
Chretienne. Since 1966 the Week of Prayer for Christian Unity has
been a joint strategy of the Vatican and the Faith and Order Commission.

ends