A history of the Church Universal must needs take some notice of those Christian communities which never acknowledged the supremacy of Rome. Chief among these stands the Church of the Eastern Empire where the Patriarch of Constantinople strove to make himself at least the equal of the Bishop of Rome. This mutual jealousy of the old and the new Rome was only one of the causes of quarrel between them, a quarrel which was fanned from time to time by the appeal of a defeated party in some ecclesiastical dispute at Constantinople to the Pope. The most famous of these disputes was that begun by the deposition of the aristocratic Ignatius from the patriarchate in favour of the learned Photius. Both Emperor and Patriarch appealed from Constantinople to Pope Nicholas I; but when that masterful bishop decided against the new patriarch, Photius used his learning to summarise in eight articles the differences between east and west. Of these, two concerned such important matters as the doctrine of the procession of the Holy Ghost and the practice of clerical celibacy. [Sidenote: Breach between East and West.] The schism made by this quarrel was healed for the moment, but for the first time the points of difference between the two Churches had been crystallised. The Eastern Emperors, however, who still possessed lands in the Italian peninsula, felt it to their interest to remain friendly with the pope, and in 1024 an attempt on the part of Basil II to adjust the question of dignity by the suggestion that both the Patriarch and the Pope should assume the title of Universal bishop, was only defeated by the inextinguishable jealousy of the Western Church. The presence of the Normans in Southern Italy should have united Pope and Eastern Emperor against the intruders; but the Greek Church only saw in the Norman successes a danger lest Southern Italy should pass from the Greek to the Latin communion, and the Patriarch Michael Caerularius joined with the Bulgarian Archbishop of Achrida in publicly warning the inhabitants of Apulia against the errors of the Latin Church. The one especially noted was the use of unleavened bread at the Sacrament, with the addition of others of even less importance. The Emperor Constantine Monomachos strove hard in the interests of peace and even compelled a literary champion of the Greek Church, Nicetas Pectoratus, a monk of the monastery of Studium, to repudiate his own arguments. But the violence of the papal envoys and the obstinacy of the Patriarch made agreement impossible. Finally the legates laid upon the altar of St. Sophia's Church a document in which Michael and all his party were anathematised; and the Patriarch responded by summoning a Council, which in like manner banned the Western Church (1054). Not only was Michael's action supported by the clergy and people of Constantinople, but it was ratified by the approval of the Patriarchs of Bulgaria and Antioch. [Sidenote: Attempts at reconciliation.]