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.
Chalcis
Chalcis (; Ancient Greek & Katharevousa: , "Chalkís") or Chalkida (Modern , ) is the chief town of the island of Euboea in Greece, situated on the Euripus Strait at its narrowest point. The name is preserved from antiquity and is derived from the Greek χαλκός (copper, bronze), though there is no trace of any mines in the area. In the late Middle Ages, it was known as Negropont(e), an Italian name that has also been applied to the entire island of Euboea.