Nicomedia

In antiquity, the capital first of the kingdom and then of the Roman province of Bithynia. Under Emperor Diocletian (AD 284–316), it was the capital of the E half of the Roman Empire.

Nicomedia (Greek: Νικομήδεια, modern İzmit) was founded by Nicomedes I of Bithynia at the head of the Gulf of Astacus (which opens on the Propontis) in 264 BC. It was the metropolis of Bithynia under the Roman empire (see Nicaea), and Diocletian made it the chief city of the Eastern Roman empire. Owing to its position at the convergence of the Asiatic roads to the new capital, Nicomedia retained its importance even after the foundation of Constantinople and its own capture by the Turks (1338).

Coordinates: 40°46′N 29°55′E