Constantine the Great was a Roman Emperor of Illyrian ancestry who ruled from 306 to 337 AD. He was a popular emperor, famous for the numerous administrative, financial, social, and military reforms he implemented to strengthen the empire. Under his rule, civil and military authorities were separated, and the government was restructured. The concept of the praetorian prefecture was formalized during his reign. Most importantly, Constantine is remembered for being the first Roman emperor to claim conversion to Christianity, making him a significant figure in the history of Christianity. Born as the son of Constantius Chlorus, a Roman army officer who later became Caesar, the deputy emperor, Constantine was destined for greatness. Valiant, intelligent, and ambitious, Constantine proved himself to be a skilled military leader. When his father was elevated to the position of Augustus, the senior western emperor, Constantine campaigned under his father in Britannia. He succeeded his father as emperor upon his death and led a series of successful civil wars against the emperors Maxentius and Licinius, vastly expanding his empire. As a devout Christian, Constantine played a pivotal role in the promotion of Christianity within the empire. While he made Christianity a favored religion, it was not formally declared the official religion during his reign. He is venerated as a saint by Eastern Orthodox Christians, Byzantine Catholics, and Anglicans.