he Gauls who
had invaded their territories about 279 B.C., and by the 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, wherein the
Byzantines were defeated. After the retreat of the Gauls Byzantium rendered
considerable services to Rome in the contests with Philip II., Antiochus
and Mithradates.

During the first years of its alliance with Rome it held the rank of a free
confederate city; but, having sought arbitration 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, which was 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.
This overthrow of Byzantium was a great loss to the empire, since it might
have served as a protection against the Goths, who afterwards sailed past
it into the Mediterranean. Severus afterwards relented, and, rebuilding a
large portion of the town, gave it the name of Augusta Antonina. He
ornamented the city with baths, and surrounded the hippodrome with
porticos; 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 position when, through the capricious resentment of Gallienus, the
inhabitants were once more put to the sword and the town was 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 the fortifications were greatly strengthened during the civil wars
which followed the abdication of Diocletian. Licinius, after his defeat
before Adrianople, retired to Byzantium, where