The chapter elaborates the issues and circumstances that led to the well-known Schism of Photius in the Byzantine Church—the murder of the logothete Theoctistus and the overthrow of the Empress Theodora in 856, the coming to power of the young Emperor Michael III and his uncle Bardas, the good relations Patriarch Ignatius had with the new rulers until he came into conflict with Bardas and then with the Emperor himself; his banishment and deposition and the consecration at the end of 858 of Photius in his place; the two councils in the Church of the Holy Apostles in 859 and 861—the first, at which Ignatius was condemned and anathematized, the interference of Pope Nicholas I and his legates at the second council and Ignatius’ attitude towards them, which compelled them to approve his sentence, contrary to the attitude of the Pope. Finally, it is related how Ignatius realized his mistake and sought the help from the Pope, which led to the papal condemnation of Photius at the Council of Rome in 863, which brought the relationship between Constantinople and Rome to the lowest point.