Constantine the Great
Learn about Constantine — the Roman emperor who legalized Christianity, founded Constantinople, and reshaped the Roman Empire.
Constantine I (c. 272–337 CE) was the Roman emperor who transformed both the empire and the Christian religion. His Edict of Milan in 313 CE ended the persecution of Christians, and his personal patronage accelerated Christianity's rise from a persecuted minority to the empire's dominant faith. He also founded Constantinople — the 'New Rome' — shifting the empire's center of gravity eastward.
Constantine's relationship with Christianity remains debated. His reported vision of a cross before the Battle of the Milvian Bridge in 312 CE ('In this sign, conquer') has been questioned by historians, and he was not baptized until his deathbed. Was his conversion sincere religious experience or political calculation? Probably both. Christianity's organizational structure paralleled the empire's own, and aligning with the church gave Constantine access to a disciplined, empire-wide network of loyal communities.
Constantine's decision to build a new capital at Byzantium — renamed Constantinople — proved equally momentous. The city's strategic location controlling the straits between Europe and Asia made it virtually impregnable. After the Western Empire fell in 476, Constantinople endured as the capital of the Byzantine Empire for another thousand years. Constantine's legacy is a world in which Christianity and political power became intertwined — a relationship that would define European history for the next millennium and a half.