Christians in North America are often unaware of one of the largest and most devoted segments of the Christian church, the Orthodox churches. During the first few centuries A.D., the church remained largely unified. But eventually, a variety of doctrinal and political disputes led to the separation of the church into roughly two main divisions, East and West.
The churches in the Byzantine tradition are those with an historic relationship to the church of Constantinople (originally Byzantium); they are familiar to North Americans as the Orthodox churches (among them the Greek and Russian). The Byzantine rite is complex and proceeds as two interwoven liturgies, one conducted with the congregation and the other performed by the celebrants behind the icon screen (iconostasis) that separates the altar from the rest of the church. The dominant theme of this liturgical tradition is the presence of Christ, both in his incarnation and in his heavenly ministry.