Like other non-Christians of his time, it seems that in the beginning
the emperor Costantino was simply monotheistic - that is, believed in a supreme creator God. known by different names and in various ways worshiped -, as the Invincible sun on its post coins 308; only a little at a time, therefore, he came to explicitly formulate, in texts of his hand, their adherence to Christianity. We have no reason to dispute, as did more than one historian, the sincerity of this conversion, although it is undeniable that it elevated him to an instrument chosen personally by God and that this personal relationship ended up taking on a political significance: we were now in a world where both pagans and Christians saw the emperor as an individual with a clear religious imprint. Nor is a sudden conversion imaginable, but rather an evolution, a gradual awakening: the same Eusebius of Caesarea, his biographer, states that the emperor received signals from God on several occasions.
It still seems that, entering Rome after the battle of Ponte Milvio (312), Constantine had found the common denominator capable of guaranteeing both the unity of the Empire - the recognition of a single God - and its own legitimacy, which he considered a personal mission conferred on him by God. A mission which, however, would never have resulted in an intolerant attitude in terms of religion. In the edict of Milan of 313 the idea that the security of the Empire was guaranteed by the supreme God found expression (and no longer by the gods of the Tetrarchy, Jupiter and Hercules) and official recognition of the impossibility of imposing religion by force. The edict was the signal of a consensus policy to which both Christians and pagans could adhere, the testimony of a common unitary foundation: a monotheism that tolerated religious differences and rejected coercion. Ending the great persecution that started in 303 gives Diocleziano proved unsuccessful in its attempt to eradicate Christianity, Constantine aimed to win over the Christians, to incorporate them into the Empire and its usual forms of politics. On the other hand, the emperor soon manifested his favors to the Church, through donations of money, lands and palaces and the financing of new basilicas in Rome and Jerusalem. Faced with the bishops' requests to intervene in their internal affairs, Constantine initially tried to resolve the conflicts peacefully, but the resistance against which he met soon led him to lash out against dissidents, at first the Donatists, then the Aryans. He always maintained an attitude of tolerance towards traditional religion (even if a little contemptuous), contenting itself with prohibiting some practices already rejected by enlightened paganism (the bloody sacrifices, the magic, personal divination). If Constantine was unable to restrain the bishops and their bitter theological disputes, he was nevertheless able, During his reign, to neutralize anti-pagan Christian militancy.
His Christian successors, in particular Constantius II, Valens and Theodosius, they continued to intervene in Church affairs. In this they were able to avail themselves of the political theology elaborated by Eusebius of Caesarea in his last writings, in particular the Speech for the Thirty Years of Reign and the Life of Constantine, in which the author proposed the model of a basileus Christian at the head of an equally Christian empire. This implied that he "subdues the enemies of truth", that he would proclaim to everyone (the laws of true piety) and watch over to ensure collective salvation. Invest in this mission of protection, indeed of surveillance, during the so-called Aryan crisis the Christian emperors supported or imposed different formulas of faith, favoring those who accepted them but persecuting those who rejected them (i dissidents, especially bishops, come Athanasius of Alexandria e Hilary of Poitiers they were deposed and exiled). At the end of fifty years of controversy, the accession to the throne of Teodosio I (379-395) marked the definitive return to orthodoxy "defined by the Council of Nicaea of 325 and reaffirmed during the council of Constantinople of 381, gaining the support of the emperor, who made it a law of universal value. A series of increasingly repressive rules limited the freedom of expression and worship of all dissidents of orthodoxy, considered heretics and as such persecuted.
Among the duties of the emperor, But, Eusebius also included that of fighting "the atheist error", paganism. Consequently, parallel to measures to crack down on Christian dissidents, Constantine's successors imposed others intended to limit and then prohibit the freedom of pagan worship. To do so first were the sons of Constantine. A law of Constantine of 341 prescribed: «Cease the superstition, the madness of sacrifices be abolished ". however, apparently, this did not translate into the absolute prohibition of authorized pagan cults, but in a simple revision of the restrictions imposed by Constantine. One of his laws in fact prohibited the destruction of temples, tolerated "even if every superstition is totally destroyed". Constantius II went further, for reasons in which politics seems to have played a certain part: between 353 and the 357, after the defeat of the usurper Magnenzio, who had again authorized the nocturnal sacrifices, numerous laws ordered the closure of temples and attempted to ban pagan worship entirely: the threat of the "avenging gladius" and the confiscation of property weighed on anyone who dared to sacrifice; the worship of statues was forbidden, on pain of death. These measures, however, they were applied only minimally. The religious policy of the two brothers never came, then, to the systematic repression of paganism, but only to his strong disapproval.
The emperor Giuliano, born a Christian and later returned to traditional religion, he abolished those prescriptions and tried to revive paganism, but his short reign (361-363) did not give him a way to complete the business. His school law, immediately abolished by his successor Jovian, it should have prohibited Christian teachers from spreading the heritage of classical culture, considered an exclusive asset of paganism. The policy of Jovian's successors, Valentiniano and Val ente, however, he remained quite tolerant of paganism. One of their first laws, repeated in 370, decreed the maintenance of freedom of worship. Towards the end of his reign, But, Valens returned to prohibit bloody sacrifices.
The religious policy of Graziano and of Theodosius I, and then only Theodosius at the disappearance of his associate, promoted much more decisive measures, which ended up outlawing paganism. Ascending the throne, Teodosio was the first to reject the title and cloak of pontefix maximus, which Graziano himself would have renounced shortly after. Christians who returned to paganism were targeted by some edicts, thus losing, in 381, the right to make a will. The law, repeated in 383, it struck severely baptized Christians who abandoned their faith, considered "excluded from Roman law", but he left to those who had only been catechumens the right to remain in favor of their own families. The legislation was tightened up by Theodosius in I. 391, with the motive that the abandonment of Christian communion was equivalent to exclusion from the rest of human beings. The ancient prohibitions concerning traditional religious practices were also restored: in 381 and 382, the bloody sacrifices were proscribed under penalty of deportation; in 38, divination practices were banned under penalty of death. The two emperors ended up lashing out against the very institutions of the cult or pagan. In the autumn of 382, Graziano had the statue and the altar of Victory removed from the Senate of Rome, therefore it suppressed the immunity of vestals and pagan priesthoods, confiscating their income and bonuses; for its part, Theodosius ordered the closure of the temples, decreeing the possibility of accessing those containing works of art only for cultural purposes or in the case of public meetings.
In 384, then, several temples were closed or demolished.
To complete the enterprise was a series of readings promulgated between 391 and the 394, aimed at prohibiting any manifestation of pagan worship: the law of 24 February 391 decreed the end of the cult in Rome, that of 16 June extended the ban to Egypt, and that of 8 November 392 to the whole empire. Under penalty of very heavy fines, as well as even more serious penalties, all kinds of sacrifices were forbidden - even the most modest ones related to domestic worship -, both publicly and privately, and regardless of the social rank of those who practiced them. With this law, which deprived traditional religion of any right to express itself, Christianity thus became the religion of the Empire: it was therefore under Theodosius (and not under Constantine, as is sometimes claimed) that the Roman Empire officially became Christian.
Bibliographic sources
History of Christianity by A. Corbin