Constantine the Great, also known as Constantine I, was a Roman emperor who ruled from 306 to 337 AD. He is known for being the first Roman emperor to convert to Christianity and for his political and military achievements. Some synonyms for Constantine the Great include Constantine I, Constantine the First, and Saint Constantine. Other synonyms may include Emperor Constantine, Constantine the Emperor, and Constantine the Blessed. Regardless of the synonym used to refer to him, Constantine's legacy continues to impact the world, particularly in regards to Christianity and the Roman Empire.