Ancient town and seaport on the Sea of Marmara, opposite Constantinople (modern Istanbul, Turkey) at the entry to Bosporus Strait. Chalcedon corresponds to modern Kadiköy, one of the suburbs of Istanbuk.
Chalcedon was an important city in the 1st millennium BCE, but would soon be made inferior due to its proximity to Byzantium, later Constantinople.
685 BCE: Founded as a colony of the Megarian Greeks.
Early 2nd century: Comes under control of the king of Pergamun (see Bergama).
133: Passes to the Romans.
451 CE: Hosts the 4th ecumenical Christian council (see Council of Chalcedon).
616: Conquered by the Persians.
626: Returned to the Byzantine Empire.
15th century: The Ottomans begin using materials of Chalcedon to building projects in Contantinople.