Constantine the Great , also known as Constantine I or Saint Constantine, was Roman Emperor

Roman Emperor

The Roman emperor was the ruler of the Roman State during the imperial period . The Romans had no single term for the office although at any given time, a given title was associated with the emperor...

 from 306 to 337. Well known for being the first Roman emperor to convert to Christianity

Christianity

Christianity is a monotheistic religion based on the life and teachings of Jesus as presented in canonical gospels and other New Testament writings...

, Constantine and co-Emperor Licinius

Licinius

Licinius I , was Roman Emperor from 308 to 324. Co-author of the Edict of Milan that granted official toleration to Christians in the Roman Empire, for the majority of his reign he was the rival of Constantine I...

 issued the Edict of Milan

Edict of Milan

The Edict of Milan was a letter signed by emperors Constantine I and Licinius that proclaimed religious toleration in the Roman Empire...

 in 313, which proclaimed religious tolerance

Religious toleration

Toleration is "the practice of deliberately allowing or permitting a thing of which one disapproves. One can meaningfully speak of tolerating, ie of allowing or permitting, only if one is in a position to disallow”. It has also been defined as "to bear or endure" or "to nourish, sustain or preserve"...

 of all religions throughout the empire.

The foremost general of his time, Constantine defeated the emperors Maxentius

Maxentius

Maxentius was a Roman Emperor from 306 to 312. He was the son of former Emperor Maximian, and the son-in-law of Emperor Galerius.-Birth and early life:Maxentius' exact date of birth is unknown; it was probably around 278...

 and Licinius

Licinius

Licinius I , was Roman Emperor from 308 to 324. Co-author of the Edict of Milan that granted official toleration to Christians in the Roman Empire, for the majority of his reign he was the rival of Constantine I...

 during civil wars.