Constantine I

American Heritage® Dictionary of the English Language, Fourth Edition

1. Constantine I 1 Known as "Constantine the Great.” Originally Flavius Valerius Constantinus. A.D. 285?-337. Emperor of Rome (306-337) who adopted the Christian faith and suspended the persecution of Christians. He rebuilt Constantinople (now Istanbul) as the new Rome (330).
2. Constantine I 2 1868-1923. King of Greece (1913-1917) who opposed the Allies in World War I and was forced to abdicate. He returned to the throne in 1920 but abdicated again (1922) after a military rebellion.

WordNet 3.0

1. n. Emperor of Rome who stopped the persecution of Christians and in 324 made Christianity the official religion of the Roman Empire; in 330 he moved his capital from Rome to Byzantium and renamed it Constantinople (280-337)