d.1059. Patriarch of Constantinople. Under his direction the final severing between the Eastern and Western churches took place, often referred to as the Great Schism of 1054. Differences between Rome and Constantinople did not originate under his regime, but went back over many centuries. The patriarch brought to his office the ability to use political power to his end. Constantine Monachus, who was emperor at the time, was negotiating with Pope Leo IX concerning the defense of S Italy against the Normans. As a part of the deal the emperor of Constantinople agreed to give back the southern Italian churches to the jurisdiction of the papacy. When Patriarch Cerularius found out about these negotiations, he decided to flex his power against the weak emperor. He began by trying to force the Latin churches in Constantinople to use Greek language and practices. When they refused in the year 1052, he closed them down.
The ritual divergences which were used as the excuse for this became the focal points of the dispute. The real issues which had been dividing them and are still dividing them, such as the equation of the papacy and the