Flavius Valerius Aurelius Constantinus
(27 February c. 272 – 22 May 337), commonly known in English
as Constantine I
, Constantine the Great
, or (among Eastern Orthodox
, Oriental Orthodox
and other Christians) Saint Constantine
, was Roman Emperor
from 306, and the undisputed holder of that office from 324 until his death in 337. 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 some Churches in union with Rome, lists both Constantine and his mother Helena as saints. In the West, he is revered under the title "The Great" for his contributions to Christianity. Constantine also transformed the ancient Greek colony of Byzantium into a new imperial residence, Constantinople, which would remain the capital of the Byzantine Empire for over a thousand years.