In Pope John Paul's letter Orientale Lumen, 'light from the east', he famously expressed the hope that the Church would once again be able to breathe with both its lungs together - a re-integrated and united Christendom depends foremost on the reconciliation of the Catholic Church of the West and the Orthodox Church of the East, together with the Oriental Orthodox Churches and the Apostolic Church of the East.

True its historic origins in the Association for the Promotion of the Union of Christendom, which brought together Anglicans, Catholics and Orthodox in the 1850s, the Catholic League for the Unity of Christians, Unitas, will be actively supporting encounter, exchange and dialogue aimed at the reconciliation of the Catholic and Orthodox Churches and especially the role of the Apostolic See of Peter in fostering unity and visible communion.

In the main, this will be through collaboration and participation with our sister societies, such as the Society of St John Chrysostom, the Society for Ecumenical Studies, the Ecumenical Society of the Blessed Virgin Mary, the Ecumenical Marian Pilgrimage Trust, the Fellowship of St Alban & St Sergius, and the East-West Meetings supported from time to time by a number of Benedictine communities.

These publications are particularly helpful in considering East-West unity:

• The Eastern Catholic Churches - A Help or Hindrance to Christian Unity?
  John Salter, Society of St John Chrysostom, London, 2006
• You Are Peter - An Orthodox Theologian's Reflection on the Exercise of Papal Primacy
  Olivier Clément, New City Press, London, 2003 (foreword by Cardinal Avery Dulles SJ)
• The Primacy of Peter
  John Meyendorff, Editor, St Vladimir's Seminary Press, New York, 1992
• Rome and the Eastern Churches - A Study in Schism
  Aidan Nichols OP, Edinburgh, 1992