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.
Monophysitism
Accepted by the sees of Rome, Constantinople, and Antioch, the Chalcedonian settlement encountered strong resistance in Alexandria (and in Egypt generally), leading ultimately to the schism between the Oriental Orthodox churches (which reject Chalcedon), on the one hand, and the so-called Chalcedonian churches on the other. The Chalcedonian churches have always considered monophysitism to be heretical and have generally viewed it as the (explicit or implicit) position of Oriental Orthodoxy. Oriental Orthodoxy, however, considers their own Christology, known as miaphysitism and based heavily on the writings of Cyril of Alexandria (whom all sides accept as orthodox), to be distinct from monophysitism and often object to being labelled monophysites.