Sometimes the Orthodox Church is called the Eastern Orthodox Church. Although our roots are in the East and most of our communities in America follow the Eastern (Byzantine) Rite, some follow the Western Rite. There is only one Orthodox Church for the whole world, East and West.
What a lot of people would consider an old Roman Catholic way of worshipping predates Roman Catholicism, which began in about AD 1054. This way of worshipping is actually an ancient Orthodox way of worshipping in the Western world. Western Rite worship looks more Anglican or Roman Catholic than the Eastern Rite, but the Western Rite is Orthodox.
A series of history lectures on the Eastern Roman Empire (aka Byzantine Empire) entitled, "12 Byzantine Rulers" is available online. Since the story of the Byzantine Empire is an essential part of the story of the Orthodox Church, it's worth listening to.
You can hear an interview with Lars Brownsworth, the lecturer, on NPR's Hear and Now. Another interview is available on The Scriptorium.
I'm a priest in the Orthodox Christian Church, the original Church founded by Christ 2,000 years ago. I serve under the jurisdiction of the ancient church of Antioch (of Syria), where the disciples were first called "Christians."