In A.D. 324 Christianity was established by Constantine as the religion
of the State, and in 330 he made Byzantium the capital of the empire.
This city on the Thracian Bosporus, founded by Greek colonists in 658
B.C., had early become a great commercial center. After being held
successively by the Athenians, Lacedæmonians, and Macedonians, it came
into Roman possession, and the new or reconstructed city Byzantium was
afterwards called _Constantinópolis_ (“City of Constantine”) and
remained the capital of the Eastern Empire of Rome till A. D. 1453.