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.
Chalcidian League
The Chalcidian League (, "Koinon tōn Chalkideōn", "League of the Chalcidians"), also referred to as the Olynthians or the Chalcidians in Thrace (, "Chalkideis epi Thrakēs") to distinguish them from the Chalcidians in Euboea, was a federal state that existed on the Chalcidice peninsula, on the shores of the northwest Aegean Sea, from around 430 BCE until it was destroyed by Philip II of Macedon in 348 BCE.