It is when The Roman Catholic Church and The Eastern Orthodox Church had The Great Schism, in which The Roman Catholic Church broke off The Orthodox Church.
The Byzantine form of Christianity was eventually called Orthodox. In 1056, the Roman and Byzantine churches split over a number of doctrinal controversies.
The Christians of the Byzantine Empire did not want to recognize the pope in Rome as their leader, so in 1054 they agreed to divide from the Catholic Church and form their own branch of Christianity. This divide was called the great schism.
The emperor after the schism of 1054 was actually an empress called Theodora. This Theodora is not the same as the wife of Justinian I though.
The Byzantine Empire's dates run from  A.D. 330 – 1453. Until the Eastern Orthodox Churches split from the Catholic Church in A.D. 1054 there were no "branches" of Christianity, there was only the Catholic Church.
The iconoclasm did not lead to any split. It led to a compromise in which statues were not to be used and icons were to be painted in the Byzantine style. The answer "The Great Schism of 1054" is often given, even though that happened due to a power feud between two bishops who got so angry they excommunicated each other.
The Great Schism of 1054 occurred among the Christians of Eastern and Western Roman Empire.
The Byzantine form of Christianity was eventually called Orthodox. In 1056, the Roman and Byzantine churches split over a number of doctrinal controversies.
The Christians of the Byzantine Empire did not want to recognize the pope in Rome as their leader, so in 1054 they agreed to divide from the Catholic Church and form their own branch of Christianity. This divide was called the great schism.
The emperor after the schism of 1054 was actually an empress called Theodora. This Theodora is not the same as the wife of Justinian I though.
in the year 1054 AD
This is not a question that really can be answered. The Eastern Orthodox Church began in the south eastern part of Europe. Its origins date back to the Roman Empire, when it was the Greek speaking part of the Catholic Church. It separated from the Roman Catholics in the East-West Schism, in 1054, at which time the most important city in its organization was Constantinople, the capital of the Byzantine Empire. But it was not limited to the Byzantine Empire, and included people of many countries.
The East-West Schism of 1054 sometimes known as the Schism of the East.
They were mostly Christian, and after 1054, split from the catholic, or universal church, and are usually referred to as "Greek Orthodox."
The Byzantine Empire's dates run from  A.D. 330 – 1453. Until the Eastern Orthodox Churches split from the Catholic Church in A.D. 1054 there were no "branches" of Christianity, there was only the Catholic Church.
The Coptic Church is a branch of the Orthodox Church with whom a schism has existed since the year 1054.
The Great Schism of 1054 and the Split of Christianity
The schism in the Christian Church (A.D. 1054) brought about two groups - the Catholic Church and the Orthodox Church in the East.