Did the Romans operate an eight-day or a nine-day week up to the time of Theodosius? And did the Greeks operate on a ten-day week?
There is no evidence that the Romans observed an eight-day or nine-day weekly cycle, or that the Greeks followed one of ten days. In fact, these nations observed no weekly cycle whatsoever. The time unit which they recognized was the lunar year and its division into twelve months as regulated by the phases of the moon. These months varied in length from twenty-nine to thirty days. This lunar year with its monthly divisions came into being largely under the influence of the agriculture needs, seasons, and festivals. Both peoples at an early date also endeavored to harmonize the lunar year with the solar cycle, but there was no week. It is true that these months were divided for the sake of convenience into certain subdivisions. The Romans divided them into three parts, but these parts did not have the significance of weeks, and varied according to the phases of the moon.
A fixed week did not become an established institution among the Greeks and the Romans until the Christian religion became the official religion of the empire. Of course, the acceptance of the Hebrew week throughout the Christian church had been prepared for by the gradual concentration of the civic life of the pagan Greeks and Romans upon the patronage of the celestial bodies which are most prominent to the observation and which were by them regarded as deities. These most prominent bodies were, of course, the sun, the moon, and the five planets known at that time. Certain days were regarded as sacred to these stellar deities. But among the Greeks and the Romans there was no such planetary weekly cycle definitely fixed until the Christian church established its weekly cycle.
Those who wish to inquire into these facts more fully will find ready reference material in Hastings' Encyclopedia of Religion and Ethics, in articles on the week or on the calendars of the nations under discussion. An excellent work of recent date is that of F. H. Colson, entitled, "The Week," Cambridge, 1926, which gathers the essential available facts on the subject. However, the reader will not find it satisfactory on the subject of the Sabbath institution in the expanding church of the Roman imperial period.
F. A. Schilling, Dean, School of Theology, Walla Walla College.