Chalcedon
Chalcedon ( or ;
, sometimes transliterated as "Chalkedon") was an ancient maritime town of Bithynia, in Asia Minor. It was located almost directly opposite Byzantium, south of Scutari (modern Üsküdar) and it is now a district of the city of Istanbul named Kadıköy. The name "Chalcedon" is a variant of Calchedon, found on all the coins of the town as well as in manuscripts of Herodotus's "Histories", Xenophon's "Hellenica", Arrian's "Anabasis", and other works. Except for a tower, almost no above-ground vestiges of the ancient city survive in Kadıköy today; artifacts uncovered at Altıyol and other excavation sites are on display at the Istanbul Archaeological Museum.
Second Council of Ephesus
The Council of Chalcedon gave rise to what has been called the Monophysite Schism between those who accepted the Second Council of Ephesus and those who accepted the Council of Chalcedon: many Byzantine emperors over the next several hundred years attempted to reconcile the opposed parties, in the process giving rise to several other schisms and teachings later condemned as heresy, such as monoenergism and monotheletism, which were devised as attempted compromises between the Chalcedonian and non-Chalcedonian parties (cf. the "Henotikon" and the Three Chapters – the latter itself leading to another schism lasting over a century, the Schism of the Three Chapters).