Until the Great Schism of 1054, what is now referred to as Roman Catholicism and Orthodox Christianity were one. This single Christian church recognized three patriarchates - Rome, Antioch, and Alexandria. Later, Constantinople and Jerusalem were added.
From the 4th century until the 10th, the two groups sparred over questions about the nature of Jesus Christ.
The major split between East and West concerned the doctrine of the "filioque" - meaning "from the son."
At the Council of Nicea in 902, Rome accepted into the Nicene Creed that the Spirit "proceeds from the Father and the Son." The Orthodox Church, on the other hand, accepts only that the Spirit "proceeds from the Father."
The Armenian, the Coptic, and the Jacobean churches of the East split from Eastern Orthodoxy over monophystism.
Those churches maintain that the nature of Jesus Christ is divine. Both Western Christianity and Orthodoxy recognize the nature of Christ as divine and human.
The Orthodox Church, formally known as the Holy Orthodox Catholic Apostolic Eastern Church has no set of creeds in the modern use of the word. It defines itself by its acceptance of the decisions of the seven ecumenical councils of the 4th to 10th centuries, and uses the same Old Testament used in the early centuries, the Septuagint.
Orthodoxy does not recognize a pope; the hierarchy culminates in the patriarchs, of which there are today 15.
The immaculate conception is not recognized, nor is the idea of purgatory. Priests may be married prior to entering the church, but not after.
Mystery and beauty receive greater emphasis in the church than doctrine and dogma. The icon has religious status as an object of worship.
Orthodoxy stresses monasticism; fasting is frequent, covering four main fasting seasons throughout the year.
Christmas is celebrated on the seventh of January. Easter is considered more important, and is held three weeks after the first full moon of the vernal equinox.