Byzantium bīzăn´shēəm, –shəm, –tēəm [key], ancient city of Thrace, on the site of the present-day İstanbul, Turkey. Founded by Greeks from Megara in 667 BC, it early rose to importance because of its position on the Bosporus. In the Peloponnesian War it was captured and recaptured by the contending forces. It was taken (AD 196) by Roman Emperor Septimius Severus. Constantine I ordered (AD 330) a new city built there; this was Constantinople, later the capital of the Byzantine Empire.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
See more Encyclopedia articles on: Ancient History, Greece