Constantine the Great is born at Naissus

Flavius Valerius Constantinus entered the world on 27 February at Naissus, in the Roman province of Moesia Superior, the city now called Niš in Serbia. His exact birth year is lost: scholars place it variously between 271 and 280, the figure traced to the patchy record-keeping of late antiquity rather than any surviving birth register.

The son of an army officer who rose to emperor, Constantine seized power after a civil war and, by 324, ruled the entire Roman world alone. He became the first Roman emperor to embrace Christianity, ending its persecution and pouring imperial wealth into building churches across the empire.

He moved the empire’s centre east, refounding Byzantium as Constantinople in 330.

That new capital outlasted Rome itself, anchoring the Eastern Roman world for more than a millennium. Constantine’s choice helped turn a once-illegal faith into the religion of an empire, a shift whose echoes still shape much of the world today.