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.
Dium (Chalcidice)
Dium or Dion () was a city on the "Acte" or "Akte" (Ακτή) peninsula (now Mount Athos), the easternmost of the three peninsulas forming the ancient Chalcidice, on its northeastern coast, north of Olophyxus. Thucydides says that among the cities of the aforementioned peninsula, Sane was colony of Andros, while Thyssus, Cleonae, Acrothoum, Olophyxus and Dium had a heterogeneous population of bilingual barbarians formed by a few Chalcidians and, the rest, Pelasgians, Bisaltians, Crestonians and Edoni. Strabo points out that its primitive populated was composed of Pelasgians from Lemnos. It was the closest city to the isthmus of the peninsula.