The growing estrangement between the Greek and Roman Churches, which had its origin in a fundamental difference in character, temperament, and ideas, became conspicuous in the fourth century, reached an incurable stage in the ninth century, and culminated in the eleventh century. Pope Nicholas I. in 863 deposed Photius from the office of Patriarch of Constantinople. Photius, in the counter synod held in 867, returned the compliment by deposing the Pope for heresy and schism.[284:1] The gulf between the East and West became practically irreparable when Nicholas I., standing firmly on the Petrine theory and backed up by the Pseudo-Isidorian Decretals, wrote to Emperor Michael: You affirm that you and your predecessors have been accustomed to command us and ours; we utterly deny it. . . . The Roman Church encompasses and comprehends within herself, she being in herself the universal church, the mirror and model of that which she embraces within her bosom. Moreover, this vessel was shown to Peter alone, and he alone was commanded to kill and eat; as in like manner, after the resurrection, he alone of all the apostles received the divine command to draw to the shore the net full of fishes. And if unto us he committed that identical commission--which is verily and indeed so committed--to embrace in our paternal arms the whole flock of Christ, is it to be believed that we surrender to you any one of those sheep whom he hath given into our keeping?[285:1]