The Roman emperor Flavius ​ ​ Valery Constantine I belongs to those few personalities in the history of mankind, about whom we can directly say that they turned the course of world history, and their works influenced the whole world and for all time. Of course, even before him in the Roman Empire there were rulers who had no less political power. But they did not have a universal idea that gave their power a world-historical meaning. After Constantine, there were rulers offering various fateful ideas to the world. But they did not have the power that only the emperor of the Roman Empire could have. The unique combination of a great idea and great power allowed Konstantin to do more than just state reform: to establish a new civilization - the Christian European civilization, which today includes countries in a colossal space from Russia to America.