Constantine the Great was the emperor of Rome for more than 30 years. Because he reigned for such a long time, he did many things. However, he is best known for three things. Two have to do with religion while the third has to do with the eventual division of the Roman Empire.
In religious terms, the first thing that Constantine is known for is the fact that he was the first emperor to embrace the Christian faith. Before Constantine, Christianity was sometimes tolerated, but Christians were sometimes persecuted by the Roman Empire. This means that it was a very important thing for Constantine to convert to Christianity. Not only did this make Christianity legal, but it also eventually made it the official religion of the empire. This was very important in the history of the world.
The second thing that Constantine did was to convene the Council of Nicaea. This council ruled that God the Father and Jesus Christ were equal members of the Trinity. It also issued the Nicene Creed. This creed is still used in many Christian churches today. This makes Constantine important to Christians.
Finally, Constantine is known for having created a secondary capital for the Roman Empire in Byzantium. The city was renamed Constantinople in his honor. Eventually, this became the capital of the Eastern Roman Empire and, still later, the capital of the Byzantine Empire.
Constantine (also known as Constantine the Great) was a Roman emperor. He was known for being the first emperor to embrace the Christian religion that was sweeping through the empire. It made Christianity legal. Before him, Christians were not accepted.