Byzantium, an ancient Greek city on the shores of the Bosporus, on a part of the site of the modern Constantinople. It was originally settled .by a band of Megarian colonists before the middle of the 7th century B. C, but it was destroyed by Otanes, the Persian satrap, in the time of Darius Hystaspis. After the defeat of the Persians at Plataea (479), Pausanias, the general of the confederate Greeks, recolonized it with a body of Dorians and Ionians. From this heterogeneous constitution endless disputes arose, and Spartan and Athenian parties always existed within the walls. The fine harbor and advantageous position soon made it of great commercial importance. It obtained possession of the corn traffic between the shores of the Euxine and Greece and Egypt, and its fisheries were abundant. The wealth of its commerce procured for the harbor of Byzantium the name of the Golden Horn. It remained under the regency of the Lacedaemonians until Cimon captured it for the Athenians; but it soon returned to its original allegiance. Alcibiades got possession of it by the aid of the Athenian party within the city, in 408; but it was retaken by Lysander the Lacedaemonian in 405. Xenophon, with the remnant of his 10,000 men, passed through it on his way homeward.
In 390 Thrasybulus expelled the pro-Lacedaemonian oligarchy, and established the power of the democracy. Byzantium put itself at the head of a league consisting of Rhodes, Chios, Cos, and Caria, threw off the Athenian supremacy, and remained for a space entirely independent. As the commercial importance of Athens declined, that of Byzantium was augmented. When, however, Philip of Macedon besieged it, it returned to its Athenian allegiance, and called upon Athens for succor. Owing to the anti-Macedonian eloquence of Demosthenes, the aid was granted, and Phocion compelled Philip to raise the siege. The Byzantines erected a monument in honor of the event, and granted the rights of Byzantine citizenship to the Athenians. During the progress of this siege the city was saved from capture by surprise, through a Hash of light which illumined the northern horizon and betrayed the proximity of the besiegers. A crescent was stamped on the Byzantine coins in honor of this miraculous event; and when the Turks took Constantinople in the 15th century, they adopted this municipal symbol as their own national device. In the reign of Alexander the Great Byzantium acknowledged the Macedonian supremacy.
In the dissensions of Alexander's generals Byzantium sided with Antigonus against Polysperchon, and with Lysimachus against Seleucus. It was at this period much exposed to the incursions of the Thra-cians, Scythians, and other barbarians, on the land side. The Gauls made it pay heavy tribute, which caused the citizens to retaliate upon the commerce of the world, by levying a toll upon all vessels passing through the Bosporus. This tax brought them into a war with the island of Rhodes, 221 B. C. Attalus, king of Pergamus, sided with the Byzantines; Prusias, king of Bithynia, with the Rhodians. The latter were successful, and commerce remained unburdened. Ancient, writers give a very bad character to the Byzantines. Their morals were not above the standard of other large seaport towns. They preferred the sound of a flute to that of a war trumpet; and when Philip of Macedon was besieging the place, the Byzantine general, Leo, found that the only means of maintaining the courage of the Byzantines, and holding them to their duty, was to plant a range of cook shops along the ramparts.
Byzantium was fortunate in allying itself with- Rome from the first against the Macedonian kings, Anti-ochus of Syria and Mithridates of Pontus. In acknowledgment of its fidelity,.the Romans allowed it to remain a free confederate city. In consequence of some popular disturbances, however, the emperor Vespasian deprived the citizens of their civic liberties and sent them a governor. In the civil war between Pescen-nius Niger and Severus, Byzantium sided with the losing claimant. The emperor Severus besieged the town, which defended itself for three years, and then capitulated from famine. The chief citizens were put to death and the massive walls razed to the ground. Subsequently he repented of this severity, embellished the town, and gave it the name of Augusta Antonina, in honor of his son Antoninus. Caracalla restored some of its former civic privileges, but Gallienus gave it up to pillage, and massacred many of the citizens. The inhabitants repelled the invading Goths in the time of Claudius II. Byzantium was the last refuge of' Licinius in his war with Constantine. After its surrender to Constantino, he resolved to build a new city on its site and make it the capital of the Roman empire.
Thus Byzantium was merged in Constantinople, A. D. 330. Dionysius and others give the old city a circumference of 40 stadia. (See Constantinople).