The Great Schism, or the separation of the Christian world into East and West, was as a result of tension between the Byzantine Empire, who held a relatively independent religious clergy, and the Papacy, along with their allies in England, Germany, France, and Spain. During the beginning of the Crusades, a series of events, which included the Crusaders’ broken promise to return cities to the Byzantine Empire, in addition to previous tension between the two, led to the rapid deterioration of relations between the Pope and the Ecumenical Patriarch, the head of the Byzantine Church. On this day in 1054, the Pope sent a delegation to convince the Byzantines to recognize Rome as the head of the Christian faith. This was only a year after the Ecumenical Patriarch of Constantinople ordered the closure of all Latin churches in Byzantium due to disagreements on the methods practiced in the Greek churches in Southern Italy. The delegation and the Ecumenical Patriarch, Michael Cerularius, disagreed, and the result was the beginning of the Schism. The Pope’s delegation excommunicated Cerularius, ending all contact between him and Rome, and in return, he excommunicated them. This was the beginning of the rivalry between the East and the West, and by 1204, when the Byzantine Empire was almost completely defeated by the increasing power of the Ottomans, the Crusaders, led by Venice, went on to sack Constantinople. The split between the churches would only begin to come to an end in the second half of the 20th century, when in 1965, the two churches made efforts at diplomacy, although there is still much to do before the two reconcile.