Chalcedon
The site of Chalcedon is located on a small peninsula on the north coast of the Sea of Marmara, near the mouth of the Bosphorus. A stream, called the Chalcis or Chalcedon in antiquity and now known as the Kurbağalıdere (Turkish: "stream with frogs"), flows into Fenerbahçe bay. There Greek colonists from Megara in Attica founded the settlement of Chalcedon in 685 BC, some seventeen years before Byzantium.
Metropolis of Chalcedon
During the Byzantine era, the metropolis of Chalcedon was always recorded in the lists of the "Notitiae Episcopatuum", where it usually ranked 9th. There is no exact information about the extent of its ecclesiastical jurisdiction, but it probably coincided with the city of Chalcedon in addition to a number settlements on the Asian shore of the Bosporus. In the early Ottoman period the area of the metropolis was expanded to the east to include Pontoherakleia (modern Ereğli) and Amastris (modern Amasra), while it also included the Princes' Islands. From the late 19th century it was further expanded and covered an extensive and narrow strip on the Black Sea coast, stretching from Rysion (modern Darıca) on the Propontis to Zonguldak.