Annually the Catholic Church, along with many other Christian churches throughout the world, celebrates the "Week of Prayer for Christian Unity" from January 18 - 25.
In recent years it is always explained that this week concludes on the feast of the Conversion of St. Paul on January 25. However, it is often forgotten that this week began on a feast of St. Peter, called the Chair of St. Peter at Rome, once celebrated on January 18.
Many Anglicans continue to celebrate a similar feast on that day called the Confession of St. Peter, focusing on the confession of faith that St. Peter gave in support of Jesus' divinity.
The choice to begin a week of prayer for Christian Unity on January 18 was a deliberate one, made by Fr. Paul Wattson, regarded as the "founder" of this week.
Octave of Prayer for Christian Unity
A 2008 article in L'Osservatore Romano explains how it came about.
This became known as the Octave of Prayer for Christian Unity, and was eventually approved by Pope Pius X in 1916.
The week, framed by these two feasts, highlights the foundation of Christian unity, built firmly on the faith of St. Peter and strengthened by the writings and example of St. Paul.
