==Background==
After the Third Century Crisis, the Roman Empire had been stabilized by a series of Illyrian Emperors. Christianity at this time had been growing more popular especially in the urban areas of the Empire, despite periodic bouts of persecution. At the time of Constantine’s birth, the empire was experiencing something of a revival under the system known as the Tetrarchy established by Diocletian. During this emperor’s reign, there was a prolonged persecution of the Christians. The Tetrarchy involved several co-Emperor’s cooperating in the administration of the far-flung Empire and its long borders </ref> Cameron, A. The later Roman Empire, AD 284-430 (Cambridge, Mass.: Harvard University Press. 1993), p 56</ref>. This system after the death of Diocletian’s main heir, Galerius, collapsed. The co-emperors who had under the Diocletian system worked together, now fought each other for supreme power and there was a civil war throughout the Empire. Constantine’s father had been one of the co-emperors. He had succeeded his father and was the de-facto ruler of much of western Europe. When Maxentius deposed the co-emperor in Italy, Constantine saw an opportunity to gain new territories. The Christian bishop Eusebius of Caesarea claimed that Constantine wanted to save Rome from a tyranny <ref> Eusebius, xviiii</ref>. Constantine had advanced quickly from his base in France but his army was significantly smaller than his enemy’s. He approached Rome and camped his army before the Milvian Bridge in 312 AD<ref>Cameron, p 113</ref>. Then according to Christian accounts, he had a dream or vision. The traditional account states that Constantine saw a Christian emblem in the sky. He saw this as a portent and this that led him to order his legionnaires to mark their shields with the Christian sign, the Chi Rho, similar to a cross. Lacentius relates how According to the Roman writer Lacentius Constantine ‘had marked on their shields the letter Χ, with a perpendicular line drawn through it and turned round thus at the top, being the cipher of CHRIST. <ref> Lactantius, De Mortibus Persecutorum Chapter XLIV </ref>. Many have seen this as proof that Constantine converted to Christianity before the Battle of the Milvian Bridge. Their argument is that after his vision that Constantine became totally committed to Christianity. The next day the army of Constantine inflicted a great defeat on Maxentius and he marched into Rome, the first Christian emperor <ref> Lactantius. X,IV</ref>. Later he defeated the ruler of the Eastern Empire and once more unified the Roman provinces under a single emperor. Constantine was a very effective ruler, he reformed the administration and rebuilt many cities, but he was an autocrat. He brought stability to the Roman empire after the civil wars and established a dynasty. Constantine also built the city of Constantinople (later Byzantium) and in doing so he laid the foundations for the medieval Byzantine Empire. His most important legacy was that he ended the persecution of Christians and legalized Christianity <ref> Cameron, p 114</ref>.
==Did Constantine Become a Christian==
Many such as the Christian writer Eusebius argued that Constantine’s order that his troops put a Christian symbol on their shields was proof his conversion before the Battle of the Milvian Bridge in 312 AD. However, it was usual for a leader to seek the support of a God. In the polytheism, prevalent in the Roman Empire, people would simply offer sacrificSe and thanks to the deity that they believed would be most likely to help them. Constantine’s instructions for his soldiers could be interpreted as merely seeking the support of the Christian God and not as a sign of his conversion to Christianity. Lacentius, a contemporary writer argued that because Constantine ordered his soldiers to display a Christian symbol <ref> Lacentius XIV</ref>, it did not mean that he had converted. Adopting a Christian symbol was a remarkable action, given that the Roman elite scorned that religion and that most of the population was pagan. However, Constantine had appeared to sympathize with the Christians during the persecution of Diocletian in particular. The Christian community in the west had been generally spared the worst effects of the persecution. There is a long-standing argument in the secondary literature that Constantine ‘conversion’ before the Milvian Bridge was a strategy to secure Christian support and to unify the empire. However, this is unlikely given the relative strengths of Christianity and paganism in the Empire <ref> Roth, J. (2013). Constantine revisited (London, Wipf & Stock Pub, 2015), p. 67 </ref> Paganism was not in any way in decline in the Empire during Constantine’s reign. In this context, Constantine’s alleged conversion would have been remarkable, especially given his ambition to unify the Roman Empire. The army was still largely pagan, and every Emperor depended on for his authority and even his life, on the soldiers' loyalty <ref> Cameron, p. 104</ref>. Then there was the Roman and Provincial nobility, who were still pagan, and every Roman Emperor needed their cooperation to control the Empire <ref>Cameron, p. 102</ref>. The fact that Constantine did order his legionaries to display a Christian symbol in battle is significant in the development of his religious beliefs. Because such a move was politically risky, in the context of the times when so many were pagan. This would suggest that Constantine did have some religious experience before the Milivian Bridge, even if it was not an outright conversion. Constantine’s experience in 312 AD, cannot be regarded as a conversion because it was not followed by his baptism and the public profession of that religion. In the 4th century, AD baptism was the final and public proof of conversion.