The Birth of Constantinople: From Greek Colony to Imperial Capital

In 324 AD, after two decades of civil war, the Roman emperor Constantine finally defeated his last rival, Licinius, at the Battle of Chrysopolis—just opposite the ancient Greek city of Byzantium on the Bosphorus. That same year, Constantine ordered the foundation of a new city on that same spot. Within six years, walls rose around a seabound peninsula jutting into the waterway that splits Asia from Europe, and Constantinople—the city of Constantine—was born. Over the next millennium, it would become one of the most consequential cities in human history.

Why This Spot, and Why Not Rome

The site of Constantinople was not chosen at random. As Professor Judith Heron explains, the location had been valued for centuries. The ancient Greeks from Megara had founded Byzantium there in the 7th century BC, recognizing its strategic command of the Bosphorus—the narrow, deep channel connecting the Aegean to the Black Sea, through which grain ships from the north and luxury goods from the east had to pass. "It has the world in its hand," Heron says, quoting a rumored remark attributed to Napoleon.