As we have already seen, the last reconciliation of the Orthodox Church with the Holy See took place at the Council of Florence in 1439. On this occasion, also, the Coptic, Abyssinian, Jacobite, Maronite, and Armenian Churches were wholly or partially united with the great Mother Church, from which they had so long been separated. It was then that the Uniate Churches already referred to had their origin. But as the reunion of the Orthodox Church had been based on political rather than ecclesiastical grounds it was of short duration, for it was formally repudiated by the Byzantines in 1472, nineteen years after the occupation of Constantinople by the Ottoman army under Mohammed the Conqueror. But, although the reunions effected at the Councils of Lyons and Florence were so short-lived, the hope of an eventual and enduring reunion has always been cherished not only by the Latins but by an influential body of the Orthodox Church as well. It will suffice here to refer to two recent efforts to secure reunion--one of which was made by the Œcumenical Patriarch, Joachim III, a little less than two decades ago, and one made by Pope Leo XIII a few years earlier. In a noted encyclical addressed to the divers Orthodox Churches, the Œcumenical Patriarch requested them to consider the question of reunion of Christendom. His courteous and charitable references in this letter to the Latin Church and his expressed hope that it and the Orthodox may again be reunited evince a man of a deeply religious spirit, whose sole object was the cause of Christ, which, as he conceived it, would be immensely advanced by the restoration of Church unity. But the replies which he received from the sister Church--those in communion with the Patriarch of Constantinople--soon convinced him that his efforts in the direction of the proposed reunion were doomed to failure.