Chalcedon

Chalcedon (; Ancient Greek: Χαλκηδών, romanized: Khalkēdṓn) was an ancient maritime town of Bithynia, in Asia Minor. It was located to the south of Chrysopolis (later known as Scutari, modern Üsküdar) and almost directly opposite Byzantium across the Bosporus strait, in Europe. At present, it is a district of the city of Istanbul named Kadıköy.

The substructures of ancient Greek buildings in Chalcedon dating from the 5th century BC are currently being excavated in the area behind the Haydarpaşa railway station, while the remnants of an older Phoenician port have been discovered in the Moda quarter. The artifacts uncovered at Altıyol and other excavation sites are on display at the Istanbul Archaeological Museum. Further inland, but still within the borders of the modern Kadıköy district, the Fikirtepe mound (which has disappeared underneath buildings) from the Chalcolithic period (c. 5500 BC), discovered in 1908, contained the oldest-known human settlement in Istanbul for almost a century, until the discovery in 2004 of the Yenikapı settlement from the Neolithic period (c. 6500 BC) on the European side of the city, during the excavation works of the Yenikapı Transfer Center of the Istanbul Metro.

The site of Chalcedon is located on a small peninsula on the north coast of the Sea of Marmara, near the mouth of the Bosporus strait. A stream, called the Chalcis or Chalcedon in antiquity and known today as Kurbağalıdere (meaning "Frog Brook" or literally "Brook with frog(s)" in Turkish), flows into Fenerbahçe Bay. There, Greek colonists from Megara in Attica founded the settlement of Chalcedon in 685 BC, some seventeen years before Byzantium.