order to throw it in the teeth of his opponents, but in this matter the Eastern Church had a real grievance to complain of. The Nicene Creed was to them what it was not to the Western Church, their only creed, and the authority of the councils, by which its form and wording were determined, stood far higher in their estimation. To add to the one and to disregard the other were, at least in their judgment, the violation of a sacred compact. The other question, which, if not actually one of doctrine, had come to be regarded as such, was that of the _azyma_, that is, the use of unfermented bread in the celebration of the eucharist. As far as one can judge from the doubtful evidence on the subject, it seems probable that ordinary, that is, leavened bread, was generally used in the church for this purpose until the seventh or eighth century, when unleavened bread began to be employed in the West, on the ground that it was used in the original institution of the sacrament, which took place during the Feast of the Passover. In the Eastern Church this change was never admitted. It seems strange that so insignificant a matter of observance should have been erected into a question of the first importance between the two communions, but the reason of this is not far to seek. The fact is that, whereas the weighty matters of dispute--the doctrine of the Procession of the Holy Spirit, and the papal claims to supremacy-- required some knowledge and reflection in order rightly to understand their bearings, the use of leavened or unleavened bread was a matter within the range of all, and those who were on the lookout for a ground of antagonism found it here ready to hand. In the story of the conversion of the Russian Vladimir we are told that the Greek missionary who expounded to him the religious views of the Eastern Church, when combating the claims of the emissaries of the Roman communion, remarked: "They celebrate the mass with unleavened bread; therefore they have not the true religion." Still, even Photius, when raking together the most minute points of difference between him and his adversaries, did not introduce this one. It was reserved for a hot-headed partisan at a later period to bring forward as a subject of public discussion. This was Michael Cerularius, Patriarch of Constantinople, with whose name the Great Schism will forever be associated.