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.
Ancient Rome
He was defeated by the Franks and the Alamanni during 306–308. In 324 he defeated another tetrarch, Licinius, and controlled all the empire, as it was before Diocletian. To celebrate his victories and Christianity's relevance, he rebuilt Byzantium and renamed it Nova Roma ("New Rome"); but the city soon gained the informal name of Constantinople ("City of Constantine"). The reign of Julian, who under the influence of his adviser Mardonius attempted to restore Classical Roman and Hellenistic religion, only briefly interrupted the succession of Christian emperors. Constantinople served as a new capital for the Empire. In fact, Rome had lost its central importance since the Crisis of the Third Century—Mediolanum was the western capital from 286 to 330, until the reign of Honorius, when Ravenna was made capital, in the 5th century.