Question

What led to the great schism between the Eastern Orthodox Church and the Roman Catholic Church

Answer 1

Schism of 1054. Schism of 1054, also called East–West Schism, event that precipitated the final separation between the Eastern Christian churches (led by the patriarch of Constantinople, Michael Cerularius) and the Western Church (led by Pope Leo IX).

Answer 2

Charlemagne's crowning made the Byzantine Emperor redundant, and relations between the East and the West deteriorated until a  split occurred in 1054. The Eastern Church became the Greek Orthodox Church by cutting off all ties with Rome and the Roman Catholic Church , from the pope to the Holy Roman Emperor on down.