“Byzantine” itself is a word freighted with a history dating back to the time of the Emperor Constantine, who legalized Christianity throughout the Roman Empire in the early 4 century A.D. He moved the center of his imperial power to a small fishing town in the Roman province of Cappadocia – Byzantium. The new imperial capital there took its name from the Emperor himself – Constantinople. Christianity in the Roman Empire developed five major centers – Rome, Jerusalem, Antioch, Alexandria, and Constantinople. All were headed by a senior bishop given the title “patriarch.”
Even before the end of the 4 century A.D., Constantinople had risen to prominence second only to Rome, the See of the Successor to St. Peter himself. While educated citizens of the Empire at first would be able to speak both Latin and Greek, over time the two language groups became distinct as the Western Empire fell into decline and disintegrated.
Worship practices came to vary as well. Indeed, before the end of the 4th century, again, many in the Eastern Empire worshipped following the Divine Liturgy attributed to St. Basil the Great (d. 379). Under the Patriarch of Constantinople, St. John Chrysostom (d. 407), a Divine Liturgy attributed to him came into prominence first in Constantinople and later throughout the Eastern Empire. Today, Byzantine Catholics worship primarily following the Divine Liturgy of St. John Chrysostom, yet still worshipping in the more flowery, deeply spiritual words of St. Basil on special liturgical occasions throughout the church year.