BYZANTIUM, bI-zin'shI•iim, the name of the city of Constantinople before its name was changed by Constantine the Great. It was founded by a colony of Greeks from Megara, who, under a leader named Byzas, settled on what seemed a favorable spot at the entrance to the Thracian Bosporus, in 658 s.c. The city, which was built by the first colonists, was named after their leader. Other colonists fol lowed from different quarters, especially from Miletus, and Byzantium was already a flourish ing town when it was taken and sacked by the Persians, in the reign of Darius, the son of Hystaspes. After the retreat of the Persians (479 s.c.) Byzantium soon recovered itself. During the Peloponnesian War it acknowledged for some time the supremacy of the Athenians, but afterward fell away. Alcibiades recovered it for Athens (409), but it was taken by Ly sander in 405. At a later period the Byzantines received support from Athens in their resistance against Philip of Macedon. The barbarian Thracians, who occupied the neighboring terri tory, and the Celts (Galatians), in their migra tions to the East, often appeared to threaten the safety of the town; but in spite of this, chiefly owing to its favorable position for com merce, it continued to prosper, and survived the decay of most of the other Greek cities; and even under the Romans it was left free to manage its own affairs, and was allowed to demand dues from all ships passing through the Bosporus, only part of these being claimed by. the Romans. At the end of the 2d century
of the Christian era Byzantium, unfortunately for itself, sided with Pescennius Niger against Septimius Severus. By the latter it was be sieged for three years, and when at last it was forced to surrender Severus ordered its walls to be razed to the ground, deprived the city of its privileges and placed it under the jurisdic tion of the Perinthians. For a time the pros perity of the city was annihilated, until a new and more brilliant era began for it under Con stantine the Great, after the defeat of Licinius in 330 A.D. Constantine made it the capital of the Roman empire, and changed its name to Constantinople (see CONSTANTINE ; CONSTANTI NOPLE). Its early form of government was that of an aristocracy, which passed into an oligarchy. In the year 390 B.c it received from Thrasybulus a democratical constitution, closely resembling that of the Athenians. Byzantium was the great entrepot for the grain trade be tween the countries bordering on the Black Sea and those bordering on the X.gean.