25 It is not just the Pope who has become a pilgrim. In recent years, many distinguished leaders of other Churches and Ecclesial Communities have visited me in Rome, and I have been able to join them in prayer, both in public and in private. I have already mentioned the visit of the Ecumenical Patriarch Dimitrios I. I would now like to recall the prayer meeting, also held in Saint Peter's Basilica, at which I joined the Lutheran Archbishops, the Primates of Sweden and Finland, for the celebration of Vespers on the occasion of the Sixth Centenary of the Canonization of Saint Birgitta (5 October 1991). This is just one example, because awareness of the duty to pray for unity has become an integral part of the Church's life. There is no important or significant event which does not benefit from Christians coming together and praying. It is impossible for me to give a complete list of such meetings, even though each one deserves to be mentioned. Truly the Lord has taken us by the hand and is guiding us. These exchanges and these prayers have already written pages and pages of our "Book of unity", a "Book" which we must constantly return to and re-read so as to draw from it new inspiration and hope.
Source: Ut Unum Sint (Vatican.va)