Constantine Constantine the Great is considered by many one of the best emperors of Roman history. Constantine was the first emperor to convert to Cristianityand also founded the great city of Constantinople which remained the capital of the eastern Romans empire until 1453. Constantine the Great was born Flavius Valerius Constantinus at Nis, in what is now Serbia, son of the commander Constantius Chlorus and Helena, a camp follower. Constantius became co-emperor in 305. Constantine, who had shown military talent in the East, joined his father in Britain in 306. He was popular with the troops, wh