Constantine was a Roman Emperor who ruled in the early 300's AD, and was arguably one of the most powerful person in his part of the world. His conversion to Christianity had far reaching effects on the common practice of the religion and on all the factions of Christianity that are present today.
His conversion happened during a war with a co-emperor, Maxentius. Constantine claimed that the night before a critical battle, in which he defeated this opponent, he had a vision of the Supreme God showing him the symbol of the cross and said, "Conquer by this." The cross was formed by the letters C (chi) and R (rho), the first two letters of the word Christ in Greek, and was the symbol that Constantine put on the shields of his soldiers. After the battle had ended, he attributed his victory to God and announced his conversion to Christianity.
Eusebius, Bishop of Caesarea, recorded this account of the Constantine's conversion.
His conversion helped Christianity in many ways. Followers were safe from persecution, and the Emperor gave Christian leaders many gifts. Constantine's adherence to Christianity ensured exposure of all his subjects to the religion, and he had no small domain. He also made Sunday an official Roman holiday so that more people could attend church, and made churches tax-exempt. However, many of the same things that helped Christianity spread subtracted from its personal significance and promoted corruption and hypocrisy. Many people were attracted to the Church because of the money and favored positions available to them from Constantine rather than from piety. The growth of the Church and its new-found public aspect prompted the building of specialized places of worship where leaders were architecturally separated from the common attendees, which stood in sharp contrast to the earlier house churches which...