Michael Cerularius (died 1058), patriarch of Constantinople (present-day İstanbul) from 1043-1058. Cerularius was patriarch at the time of the schism of 1054, which formally separated the Eastern Orthodox church from the Western Roman Catholic church. In 1043, three years after he became a monk, he was named patriarch by the Byzantine emperor Constantine IX, with whom he had conspired to overthrow the previous emperor, Michael IV. Cerularius was stridently anti-Latin and particularly resentful of Rome's claim of primacy over all Christendom. In 1054 a legation sent by Pope Leo IX issued a bull excommunicating him and the whole Eastern church. Cerularius answered by rejecting the papal assertion of supremacy and presenting an encyclical asserting Byzantine independence from and equality with the Western church. Cerularius also asserted the superiority of the church over the state, a position that led to his eventual dethronement and exile by the Byzantine emperor Isaac I Comnenus.