Answer:
The Byzantine Empire was a vast and powerful civilization with origins that can be traced to 330 A.D., when the Roman emperor Constantine I dedicated a “New Rome” on the site of the ancient Greek colony of Byzantium. Though the western half of the Roman Empire crumbled and fell in 476 A.D., the eastern half survived for 1,000 more years, spawning a rich tradition of art, literature and learning and serving as a military buffer between Europe and Asia. The Byzantine Empire finally fell in 1453, after an Ottoman army stormed Constantinople during the reign of Constantine XI.
Byzantium
The term “Byzantine” derives from Byzantium, an ancient Greek colony founded by a man named Byzas. Located on the European side of the Bosporus (the strait linking the Black Sea to the Mediterranean), the site of Byzantium was ideally located to serve as a transit and trade point between Europe and Asia.
In 330 A.D., Roman Emperor Constantine I chose Byzantium as the site of a “New Rome” with an eponymous capital city, Constantinople. Five years earlier, at the Council of Nicaea, Constantine had established Christianity — once an obscure Jewish sect — as Rome’s official religion.
The citizens of Constantinople and the rest of the Eastern Roman Empire identified strongly as Romans and Christians, though many of them spoke Greek and not Latin
Though Constantine ruled over a unified Roman Empire, this unity proved illusory after his death in 337. In 364, Emperor Valentinian I again divided the empire into western and eastern sections, putting himself in power in the west and his brother Valens in the east.
The fate of the two regions diverged greatly over the next several centuries. In the west, constant attacks from German invaders such as the Visigoths broke the struggling empire down piece by piece until Italy was the only territory left under Roman control. In 476, the barbarian Odoacer overthrew the last Roman emperor, Romulus Augustus, and Rome had fallen.