Eastern and Western traditions of the Chalcedonian Christian Church reached a terminal crisis

In 1054, relations between the Eastern and Western traditions of the Chalcedonian Christian Church reached a terminal crisis, known as the East-West Schism. Although there was a formal declaration of institutional separation, on 16 July, when three papal legates entered the Hagia Sophia during Divine Liturgy on a Saturday afternoon and placed a bull of excommunication on the altar, the so-called Great Schism was actually the culmination of centuries of gradual separation.