Prof. Hutton Webster admitted it.....

Remember the sabbath day, to keep it holy.   

Six days shalt thou labor, and do all thy work:

But the seventh day is the sabbath of the LORD thy God: 

in it thou shalt not do any work, thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor thy stranger that is within thy gates: Exodus 20:8-10

"Prof. Hutton Webster, of the University of Nebraska, says:

"This legislation by Constantine probably bore no relation to

Christianity; it appears, on the contrary, that the emperor, in his capacity of Pontifex Maximus, was only adding the day of the sun, the worship of which was then firmly established in the Roman Empire, to the other ferial days of the sacred calendar."

"What began, however, as a pagan ordinance, ended as a Christian regulation; and a long series of imperial decrees, during the fourth, fifth, and sixth centuries, enjoined with increasing stringency abstinence from labor on Sunday."—"Rest Days," pp. 1SS, S70." W.A. Spicer