The Great East-West Church Division: Eastern Orthodox and Roman Catholic (Constantinople) (AD 1054)
Although the division between the Eastern Orthodox Church and the Roman Catholic Church was a long and gradual process, church historians have identified an event in 1054 as a significant breaking point.
In that year, representatives of the Roman Catholic Pope Leo IX (1049-1054) traveled to Constantinople from Rome with a letter for bishop Michael Cerularius (1043-1059). The letter demanded that the eastern church submit to the Roman Catholic Church’s authority over the universGal church.
Because Cerularius refused to submit to Rome, on July 16, 1054, Cardinal Humbert—the representative of Leo IX— marched up to the main altar of the Church of Holy Wisdom (Hagia Sophia) during afternoon prayers and angrily dropped an edict excommunicating Cerularius. He then marched out of the church, shook the dust from his feet, and left Constantinople.
In return, Cerularius excommunicated the Roman Catholics. These events caused a major division between the Eastern Orthodox and Roman Catholics that still exists today, although sincere actions on both sides have recently been taken to reestablish church unity.