Naissus, today Niš,Serbia, February 27th c. 272-Nicomedia, now Izmit, Turkey, May22, 337
Also known as Constantine the Great, he was the Roman emperor who legitimized Christianity and ended the persecution of practitioners of this religion.
He became emperor after the death of his father since the year 306, but ascended as Emperor of the Western Roman Empire in 312. Prior to the Battle of the Milvian Bridge, he had a dream in which a burning cross appeared in the sky accompanied by the words “in this sign conquer.” Constantine used crosses in the banners of his army and effectively won the battle.
After this episode he granted religious freedom by the Edict of Milan in 313 and ended with the era of martyrs. Christians obtained Rights such as the return of their confiscated property, he supported the construction of churches and declared Sunday a day of rest.
Three years later he conquered the Eastern Roman Empire, became sole emperor and founded the city of Constantinople where Byzantium was once located. In 325 he convened the Council of Nicaea, in which the equality of God the Father and God the Son was established by establishing the doctrine of the Trinity, and implemented the Nicene Creed, deifying the figure of Jesus.
Constantine is usually considered the first Christian Roman emperor, although his conversion took place at his deathbed. His laws changed history and led to the adoption of Christianity as a popular religious belief in Western Europe.