"The Catholic Church ... considers it her duty to work actively so that there may be fulfilled the great mystery of that unity which Jesus Christ invoked with fervent prayer from his heavenly Father on the eve of his sacrifice." The initial decision to invite non-Catholic observers to the Second Vatican Council was made by Pope John himself; it was the first Council to which Christians not in communion with the Catholic Church had been invited. By the end of the Council their numbers had grown to close on one hundred. According to Cardinal Franz Knig (3), they had a positive influence on the ecumenical climate and their role grew as the Council progressed. The end of the council was marked by a service in St Peter's on 7 December 1965. Cardinal Knig recalled: "I was one of a small group on the altar with Pope Paul VI. After asking the representative of the Ecumenical Patriarch of Constantinople to join him there, the Pope announced that the Papal Bull of 1054, which had declared the Great Schism between the Western and Eastern Church, was now null and void. I can still hear the thundering burst of spontaneous applause with which this announcement was received. For me this highlight signalled that the impulses set off by the council were already at work. The crucial process of reception, that all-important part of any church council, which can take several generations, had begun. It continues today." The basis of the Catholic Church's commitment