Constantine's reign as Roman emperor (A.D. 306-337) dramatically changed the direction of Christianity, though in ways far different from those portrayed in The Da Vinci Code. This grew out of his strategy for unifying his empire by creating a "catholic"—meaning universal —church that would blend elements from many religions into one.
While Constantine supposedly converted to Christianity in 312, he wasn't baptized until on his deathbed 25 years later. In the intervening years he had his wife and eldest son murdered, and from all appearances he continued as a worshipper of the sun god. Long after his supposed conversion he had coins minted with a portrait of himself on one side and a depiction of his "companion, the unconquered Sol [sun]" on the other.
The "Christianity" Constantine endorsed was already considerably different from that practiced by Jesus Christ and the apostles. The emperor accelerated the change by his own hatred of Jews and religious practices he considered Jewish.
For example, at the Council of Nicea (A.D. 325), church authorities essentially replaced the biblical Passover with Easter, a popular holiday rooted in ancient springtime fertility celebrations. Endorsing this change, Constantine announced: "It appeared an unworthy thing that in the celebration of this most holy feast [Easter] we should follow the practice of the Jews, who have impiously defiled their hands with enormous sin, and are, therefore, deservedly afflicted with blindness of soul . . . Let us then have nothing in common with the detestable Jewish crowd" (Eusebius, Life of Constantine 3, 18-19, Nicene and Post-Nicene Fathers, 1979, second series, Vol. 1, pp. 524-525).
Constantine's affection for sun worship had earlier led him to endorse Sunday, the first day of the week and a day dedicated to honoring the sun, as a weekly day of rest in the Roman empire . This created considerable hardship on those Jews and true Christians who continued to keep the biblical Sabbath on the seventh day of the week. (A century later the Council of Laodicea would essentially outlaw Sabbath-keeping and Christian observance of the biblical Holy Days.)
British historian Paul Johnson summarizes how Constantine's approach of merging religious practices produced a corrupted Christianity that meshed paganism with biblical elements: "Thus the followers of Isis adored a madonna nursing her holy child; the cult of Attis and Cybele celebrated a day of blood and fasting, followed by the Hilaria resurrection-feast . . . the elitist Mithraics, many of whom were senior army officers, ate a sacred meal ...
"Many Christians did not make a clear distinction between this sun-cult [Mithraism] and their own. They . . . held their services on Sunday, knelt towards the East and had their nativity-feast on 25 December, the birthday of the sun at the winter solstice ...
"How could the Christian Church, apparently quite willingly, accommodate this weird megalomaniac [Constantine] in its theocratic system? Was there a conscious bargain? Which side benefited most from this unseemly marriage between Church and State? ... Did the empire surrender to Christianity, or did Christianity prostitute itself to the empire?" ( A History of Christianity, 1976, pp. 67-69).
When we consider the vast differences between the mainstream Christianity of today and the original Christianity of Jesus Christ and the apostles, we can trace much of that change to Constantine and the religious system he put in power. GN