Constantine the Great

Constantine the Great is a Roman emperor from AD 306 - 337 whose policies and choices reshaped not only the Roman Empire but also the world. His acceptance of Christianity and his establishment of an eastern capital city, which would later bear his name, mark his rule as a significant pivot point between ancient history and the Middle Ages. As an emperor, Constantine united the whole of the Roman Empire under one ruler. By 324 he had extended his power and was sole emperor, restoring stability and security to the Roman world.

Constantine also abandoned Rome as the most important city in the empire, building a new capital modestly named Constantinople (now Istanbul). In the next two centuries, Rome, Italy became vulnerable to barbarian invasions. The much more easily defensible Constantinople lasted for another thousand years.