an ancient Greek city on the shores of the Bosporus, which occupied the most easterly of the seven hills on which the modern Constantinople has been built. It is said to have been founded by a band of Megarians B.C. 667, but the original settlement having been destroyed in the reign of Darius Hystaspes by the Satrap Otaeus, it was recolonized by Pausanias, who wrested it from the hands of the Medes after the battle of Platæa—a circumstance which has led several ancient chroniclers to ascribe its foundation to him. The advantages of its situation as a place of commerce, which are said to have been pointed out to the Megarians by the oracle of Apollo—in the same way that its boundaries were afterwards revealed to Constantine by an invisible guide—quickly gave it pre-eminence over the other Dorian colonies on the coast. Its position on the Bosporus gave it complete control of the extensive corn-trade carried on by the merchants of the west with the northern shores of the Euxine, the absence of tides and the depth of its harbour rendered its quays accessible to vessels of large burden without the intervention of boats, while the pelamys and other fisheries at the mouth of the Lycus were so lucrative as to procure for the deeply curved bay into which that river fell the appellation of the Golden Horn. The greatest hindrance to its continued prosperity consisted in the miscellaneous character of the population, partly Lacedæmonians and partly Athenians, who flocked to it under Pausanias. From this circumstance it was the subject of dispute between both the states, and alternately in the possession of each, till it achieved its independence of both only to fall into the hands of the Macedonians; and from the same cause arose the violent contests of its intestine factions, which ended in the establishment of a rude and turbulent democracy. About seven years after its second colonization, Cimon wrested it from the hands of the Lacedæmonians; but it soon after revolted, and returned to its former allegiance. Alcibiades, after a severe blockade (B.C. 408) gained possession of the city through the treachery of the Athenian party; and it continued an ally of Athens until B.C. 405, when it was retaken by Lysander after the battle of Aigos-potamoï. It was under the Lacedæmonian power when the Ten Thousand were quartered in it after the retreat; when exasperated by the conduct of the governor, they mutinied and made themselves masters of the city, and would have pillaged it had they not been repressed by the firmness and promptitude of Xenophon. In B.C. 390 Thrasybulus, with the assistance of Heracleides and Archebius, succeeded in expelling the Lacedæmonian oligarchy, and in restoring the Athenian interest both in Byzantium and Chalcedon. By his influence also the government was changed into a democracy; and under the new constitution, as under the former oligarchy, the native Bithynians, into whose territories the colonists of Byzantium and Chalcedon had for half a century been making joint inroads, suffered the degradation and misery of Helots. After having withstood an attempt under Epaminondas to restore it to the Lacedæmonians, Byzantium joined with Rhodes, Chios, Cos, and Mausolus King of Caria, in throwing off the Athenian yoke, but soon returned to its allegiance when besieged by Philip of Macedon, after he had overrun Thrace. The succours which were sent by the Athenians under Chares, on their arrival suffered a severe defeat from Amyntas, the Macedonian admiral; but in the following year they gained a decisive victory under Phocion, and compelled Philip to raise the siege. The wonderful deliverance of the besieged from a surprise, by means of a flash of light which illuminated the northern horizon and revealed the advancing masses of the Macedonian army, has rendered this siege peculiarly memorable.

As a memorial of the miraculous interference the Byzantines erected an altar to Torch-bearing Hecate, and stamped a crescent on their coins as a symbol of the portent, a device which is retained by the Turks to this day. In gratitude for the Athenian succours, procured chiefly by the eloquence of Demosthenes, they granted the Athenians the right of isopolicy, coupled with extraordinary privileges, and erected a monument in honour of the event in a public part of the city. During the reign of Alexander, Byzantium was compelled to acknowledge the Macedonian supremacy; and after the decay of the Macedonian power, although it regained its independence, it suffered from the repeated incursions of the Scythian hordes which overran the unprotected province. The losses which they sustained by land roused the Byzantines to indemnify themselves on the vessels which still crowded the harbour, and the fleets of merchantmen which cleared the straits; but this had the effect of provoking a war with the neighbouring naval powers. The exchequer being drained by the payment of 10,000 pieces of gold to buy off the Gauls who had invaded their territories about the year 279 B.C., and the subsequent imposition of an annual tribute which was ultimately raised to 80 talents, they were compelled to exact a toll on all the ships which passed the Bosporus; a measure which the Rhodians resented and avenged by a war, in which, though supported by Attalus King of Pergamus, they were defeated, and obliged to sue for peace on very disadvantageous terms. The subsequent retreat of the Gauls to Asia gave Byzantium another opportunity of regaining its independence, and enabled it to render considerable services to Rome in the contests with Philip II. of Macedon, Antiochus, and Mithridates. During the first years of its alliance with Rome it held the rank of a free and confederate city; but having sought the arbitration of the capital on some of its domestic disputes, it was subjected to the imperial jurisdiction, and gradually stripped of its privileges, until reduced to the status of an ordinary Roman colony. In recollection of its former services, the Emperor Claudius remitted the heavy tribute which had been imposed on it; but the last remnant of its independence was taken away by Vespasian, who, in answer to a remonstrance from Apollonius of Tyana, taunted the inhabitants with having "forgotten to be free." During the civil wars, it espoused the party of Pescennius Niger; and though skilfully defended by the engineer Periscus, it was besieged and taken (A.D. 196) by Severus, who destroyed the city, demolished the famous wall built of massive stones so closely riveted together as to appear one block, put the principal inhabitants to the sword, and subjected the remainder to the Perinthians.

Severus, however, afterwards relented, and rebuilding a large portion of the town, gave it the name of Augusta Antonia. He ornamented the city with baths, and surrounded the hippodrome with porticoes; but it was not till the time of Caracalla that it was restored to its former political privileges. It had scarcely begun to recover its former flourishing position when, from the capricious resentment of Gallienus, the inhabitants were once more put to the sword, and the town given up to be pillaged. From this disaster the inhabitants recovered so far as to be able to give an effectual check to an invasion of the Goths in the reign of Claudius II., and its fortifications were greatly strengthened during the civil wars which followed the abdication of Diocletian. Licinius, after his defeat before Adrianople, retired to Byzantium, where he was besieged by Constantine, and compelled to surrender. To check the inroads of the barbarians on the north of the Black Sea, Diocletian had resolved to transfer his capital to Nicomedia; but Constantine, struck with the advantages which the situation of Byzantium presented, resolved to build a new city there on the site of the old, and transfer the seat of government to it. The design was quickly put into execution, and the new capital was inaugurated with special ceremonies, A.D. 330. See Constantinople.

The ancient historians invariably note the profligacy of the inhabitants of Byzantium. They are described as an idle and depraved people, spending their time for the most part in loitering about the harbour, or carousing over the fine wine of Maronea and the neighbourhood. In war they trembled at the sound of a trumpet, in peace they quaked before the shouting of their own demagogues; and during the assault of Philip II. they could only be prevailed on to man the walls by the savour of the extempore cook-shops distributed along the ramparts.