I shall answer your questions briefly, and in the order in which you sent them.
1. The pagan Greeks and Romans never had a weekly day of rest.
2. They never had a weekly holiday or festival day.
3. They never had a special day in the week on which they made offerings or prayers to heathen gods. (Neither the pagan Greeks nor the Romans recognized a seven-day division or week division in the month.)
4. They made no offerings or prayers on Sunday to their gods any more than on other days.
5. The seven-day period of dividing the month or the week was never adopted into the calendar of the pagan Greeks. It appears in the Roman calendar after the time of Theodosius, or after 391 A.D., but the week, or seven-day period, first appears in Roman law in a constitution of Constantine, promulgated in 321 A.D. This appears in the Code of Justinian.
The seven-day division of the month, which is, of course from the stand point of the calendar, a pretty cumbersome method of division, comes from the ancient Hebrews, whose Sabbath, falling on every Saturday, early became a period of rest. The word, Sabbath, means, probably, the “divider.” The early Christians, for example, Paul, did not think it necessary for the Christian communities to observe the Jewish Sabbath. Usually, however, they did observe it. In the first two centuries of our era they developed the custom of observing the Lord’s Day with prayer and common meals, and out of this, and the Jewish day of rest, arose our practice of observing Sunday.
I have been very glad to be of service to you.
Sincerely yours, W. H. WESTERMAN
Dear Sir: I will again answer your questions in the order in which you asked them of me.
1. In the constitution of Constantine of A.D. 321, which spoke of the “venerable day of the sun,” Constantine regards Sunday as venerable undoubtedly from the Christian standpoint. It had been so regarded by the Christians since the second century, as the day of the Resurrection.
It would, therefore, be venerable to Constantine, who had already legalized the Christian religion. If it was in any way venerable or a holiday to the pagans, so far as my information goes, the pagans must have adopted the practice from the Christians.
2. Apollo was not worshiped on any stated day of the week or month more than any other.
3. I do not believe that there is any proof that the early Christians were led to observe Sunday by the example of any pagan worship upon that day. Indeed, I think Tertullian’s statements, quoted by you, from Chapter XVI of his “Apology,” goes to show that the pagans did not worship the sun upon that day, rather than the opposite.
Very sincerely yours, W. H. WESTERMAN
The united testimony of these high authorities is decisive. Neither the pagan Romans nor the Greeks had any weekly day of rest from work, or any weekly festival, or any weekly day for worship. They made no use of a week of seven days for anything. Professor Moore says it had no use in common life. Notice further: The old astrological week of seven days had no rest day.
The idea of a rest day once a week was unknown to the pagan Romans and Greeks till they learned it of the Jews and Christians centuries after Christ. The edict of Constantine, A.D. 321, was the very first time the week of seven days was recognized in Roman law. All history agrees in this and it is a decisive fact showing that, up to that date, the Romans had made no use of our week of seven days, hence, did not, and could not, have observed Sunday as a day of rest.
There was no religious idea connected with the naming of the days from the planets, as Sunday from the sun, Monday from the moon, etc.
All four of these specialists in ancient history agree in answering these questions though neither one knew that they had been submitted to the others; yet all four exactly agree in every particular, though widely scattered, London, Washington, Massachusetts, and Wisconsin. Such a unanimous agreement would settle any question in a court of law.
Source: The Lord’s Day From Neither Catholics nor Pagans – D.M. Canright