When Emperor Constantine established a permanent day of rest empire-wide in 321 CE, he wrote, “All magistrates, city dwellers and artisans are to rest on the venerable day of the Sun.” He was no doubt happy to choose a day that had significance for Roman Christianity and that happened to coincide with his devotion to the sun god Apollo. Absent from his decree was any mention of Christ or “the Lord’s day”; he only mentioned veneration of the sun. A.H.M. Jones notes that it seems the emperor “imagined that Christian observance of the first day . . . was a tribute to the unconquered sun” (Constantine and the Conversion of Europe).
The emperor expressed hatred of all things Jewish (and from his perspective that would surely include the Sabbath) when he set about establishing the date for the celebration of Easter. He formalized the method still used today: Easter Sunday is the first Sunday following the first full moon after the vernal equinox, when the sun’s position marks the beginning of spring. This was the practice of the churches at Alexandria in Egypt and in the West when Constantine came on the scene, whereas the churches in the East established the date based on the Jewish Passover.
While the sun’s position was part of the new method of calculation, in this case it was probably Constantine’s hatred of the Jews rather than his devotion to Apollo that caused him to insist on the change. As he wrote in a summary letter, “Let there be nothing in common between you and the detestable mob of Jews! . . . with that nation of parricides and Lord-killers” (Eusebius, Life of Constantine 3.18.2; 3.19.1).
If Constantine had considered that according to Jesus, the Sabbath was made for man, traditional Christianity might have been on a very different path.