The Sol Invictus started in the Roman Empire. This deity was originally pagan, then, through historical processes of which we still don’t know the exact nature, it became part of the Christian tradition. during the reign of Emperor Constantine I, who governed between 306 and 337.
By the second half of the third century, between 270 and 275, the Roman Empire had started to crumble apart. In the Orient, Zenobia, the Queen of Palmyra, annexes a part of Asia Minor and the whole of Egypt… Her empire needs to be reduced and it will be the Emperor Aurelian, (270-275) who does that. (He will later be murdered by his officers). He was then forced to return to the West, where roman senators founded a Gaul empire. He is then forced into battle again. He was thus a rather bellicose emperor, constantly engaged in combat, and died during the war in 275, near Byzantium. He also had to unify his empire in terms of religion. The cult of the emperor, that had reached its height with Cesar Augustus at the beginning of our era, had started to lose ground. What did he replace this cult with? Well, he finds an answer in the Cult of Apollo and especially in the Cult of Mithras, but also in the entire Mesopotamian basin, which abounded in solar worship. He therefore invented this formula – at least we think it was him – the notion of Sol Invictus . He doesn’t make it a State religion, but a religion in the State. It is not a monotheism, with the Sun as the only God, but it is a religion on top of other religions. It is therefore a syncretism of which the Sol Invictus is the core. It is no longer Aurelian himself who represents God, but the Sol Invictus to which he refers.
Aurelian died in 275… A number of emperors succeeded him until 284 when the bloodthirsty, anti-Christian Diocletian came to power. Under his reign, Christians were persecuted until 305. In 306 Constantine I came to power. At the beginning of his reign, he had gold medallions minted that represent him with the Sol Invictus . Constantine converted to Christianity around 313 by a complex process, which is still debated today. He comes to identify The Sol Invictus with the Christ, the true sun, which had already taken over the entire Roman Empire, despite the terrible persecutions, particularly under Diocletian.
The great sun will therefore be the Christ and some changes occur in the calendar. On the 7th of March 321, for example, one of Constantine’s laws made Sunday, the day of the sun, a day of rest. Aurelian had already started this, by declaring that the day on which the day starts taking over the night, around the 25th of December will be the “day of the Sun”, the “day of the Sol Invictus ”, which was then simply assimilated by the Christians in a process that has been more or less established today.
This is what we can say about the Sol Invictus , the Christ. I must however add, as a philosopher, and more precisely as a theologian, that faith in Christ is something completely different today. It is based on four major texts, the four Gospels, it is a matter of belief in the truth of these texts of belief in the person of Christ, As well as being a reflexive engagement developed over the last 60 years or so as a discipline called Christology which constitutes a contemporary development of the reflection on the person of Christ, which is equalled only by a period between the second and sixth century during the patristic era, the era of the great Fathers of the Church: Origen, Athanasius, Clement of Alexandria, Cyrille of Alexandria, and the Latin Ambrose, Augustine, Cyprian and Tertullian. The contemporary wave of thought develops the personality of Christ on a philosophical and theological level, with the tools of modern philosophical thought.