A British cardinal encouraged Christians to overcome the "three enemies of ecumenism" and to pray for the progress of closer unity.
Cardinal Cormac Murphy-O'Connor, retired archbishop of Westminster, said "suspicion, inertia and impatience" had damaged the ecumenical project.
Prayer and grassroots initiatives are the best means of keeping the ecumenical dream alive, he said.
"To mend the ruptures of the past is a task that devolves on each one of us here this evening," the cardinal said at the Jan. 22 service for the Week of Prayer for Christian Unity.
"When we meet together and pray together, the suspicions of the past dissolve, and we reach the heart of the ecumenical movement, which is a spiritual movement focused on Jesus Christ, the Son of God, to whom we pray and in whom we reach the Father."