Constantinople
Constantinople (; ) was the capital city of the Roman/Byzantine Empire (330–1204 and 1261–1453), and also of the brief Crusader state known as the Latin Empire (1204–1261), until finally falling to the Ottoman Empire (1453–1923). It was reinaugurated in 324 from ancient Byzantium as the new capital of the Roman Empire by Emperor Constantine the Great, after whom it was named, and dedicated on 11 May 330. The city was located in what is now the European side and the core of modern Istanbul.
History of Istanbul
Constantine’s conversion to Christianity a few years earlier, in 312, had set the Roman Empire onto Christianization, and in 381, during the reign of Theodosius I, the official state religion of the Roman Empire became Christianity, which turned Constantinople into a thriving religious center. After the end of his reign in 337, Constantine declared his three sons as joint heirs of the Roman Empire in a system of co-emperorship. Unfortunately, the sons couldn’t govern together peacefully and their war raged rivalry split the empire on the north-south line along the Balkan Peninsula. The territory was officially split in 395 when Theodosius I (ruled, 379-395) died leaving his son Arcadius emperor of the eastern half of the empire and his other son Honorius emperor of the western half.