Nicomedia

Nicomedia (on the site of present-day Izmit, Turkey) was located at the end of a long northeastern arm of the Sea of Marmara. It was the capital of Roman Bithynia, and when Diocletian established the tetrarchy he made it the senior capital of the Eastern Empire. The city played a significant role in the early crusades but fell to the Ottomans in 1337. While the Byzantines managed to retake it temporarily in 1402, the Ottomans reclaimed control permanently in 1419. Spelling note: By Dati's day, most European maps use a version of this toponym that omits the first syllable, so the Sfera maps usually label it as comidia or commedia. Campbell #1325.