Constantine I [The Great] (AD 307 – AD 337)
Caesar Flavius Valerius Aurelius Constantinus Augustus, commonly known in English as Constantine I. Best known for being the first Christian Roman emperor, Constantine reversed the persecutions of his predecessor, Diocletian, and issued (with his co-emperor Licinius) the Edict of Milan in 313, which proclaimed religious toleration throughout the empire. The Byzantine liturgical calendar, observed by the Eastern Orthodox Church and Eastern Catholic Churches of Byzantine rite, lists both Constantine and his mother Helena as saints. Although he is not included in the Latin Church’s list of saints, which does recognize several other Constantines as saints, he is revered under the title “The Great” for his contributions to Christianity. Constantine also transformed the ancient Roman colony of Byzantium into a new imperial residence, Constantinople, which would remain the capital of the Byzantine Empire for over one thousand years.