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 (Aetolia)
Chalcis or Chalkis (), also called Chalceia (Χάλκεια) and Hypochalcis (Ὑποχαλκίς), was a town of ancient Aetolia, situated upon the coast, at a short distance east of the mouth of the Evenus, and at the foot of a mountain of the same name, whence it was called Hypochalcis. Chalcis is one of the five Aetolian towns spoken of by Homer, who gives it the epithet of ἀγχίαλος ("anchialos", "near the coast"), in the Catalogue of Ships in the "Iliad". It continued to be mentioned in the historical period, by Thucydides, Polybius, and Strabo.