The ancient name for Istanbul is Byzantium. This city, founded by the Greeks in the 7th century BCE, was later renamed Constantinople after Emperor Constantine the Great made it the capital of the Roman Empire in 330 CE. The name "Istanbul" originated in the 10th century and became the city's official name in the early 20th century. The city's rich history is marked by various civilizations, including the Byzantines and Ottomans, contributing to its diverse cultural heritage that remains significant today.