Flavius Valerius Aurelius Constantinus, born February 27, 272, is commonly known as Constantine I or Constantine the Great. He was proclaimed Augustus by his troops on July 25, 306, and ruled an ever-growing portion of the Roman Empire to his death. Constantine is famous for his rebuilding of Byzantium as "Nova Roma" (New Rome), which was always popularly called "Constantine's City" (Constantinopolis, Constantinople). With the Edict of Milan in 313, Constantine and his co-Emperor Licinius removed all onus from Christianity. By taking the personal step of convoking the Council of Nicaea (325), Constantine began the Roman Empire's unofficial sponsoring of Christianity, which was a major factor in that religion's spread. His reputation as the " first Christian Emperor" was promulgated by Lactantius and Eusebius of Caesarea, gaining ground in the succeeding generations.

             He was born at Naissus, (today's Niš, Serbia, Serbia and Montenegro) in Upper Moesia, to Constantius I Chlorus, who was of Greek descent, and an innkeeper's daughter, Flavia Iulia Helena, who at the time was an adolescent of only 16 years. She "may not have been married to Constantius I Chlorus, - who as a high officer could have found it difficult to marry a non-Roman wife - although some modern authorities refuse to accept this view, out of a pious determination to regard Constantine as legitimate."1 His father left his mother in 292 to marry Flavia Maximiana Theodora, daughter or stepdaughter of Western Roman Emperor Maximian. Theodora would give birth to six half-siblings of Constantine, including Julius Constantius. Family influence is thought to account for a personal adoption of Christianity: Helena is said to be probably born a Christian, though virtually nothing is known of her background, save that her mother was the daughter of an innkeeper and her father a successful soldier, a career that excluded overt Christians.