OK. I have some bits of information about the concept of seven-day weeks, but I’m not sure how they all tie together.
Israel had a 7-day week based on the existence of the “Sabbath” or day of rest.
Greece and Rome had a 7-day week based on (presumably Babylonian) astrology. This arose from taking the hours of the day (12 hours from dawn to dusk, 12 more hours from dusk till dawn), and assigning the planets to them, according to the speed of their motion (Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon). Now, the planet which ruled dawn on a given day was called the ruler of that day. Since there are 24 hours and 7 planets, every day the hour of dawn would be ruled by a planet 3 places down on the above list (SATURN-day jupiter mars SUN-day venus mercury MOON-day saturn jupiter MARS-day [Tuesday] and so on).
The Hebrew name for Saturn is “The Sabbath [planet]”. (Shabbathai or something like that).
Now, is it just a coincidence that Israel had a 7-day Sabbath week and the Greeks and Romans also had a 7-day astrological week, or is there an old Babylonian connection there?
When did the Hebrew name for the Sabbath appear? Was it created by Jews who knew about the Roman/Greek astrological week, so the reasoning went, “Saturn is the planet which according to the goyim is the astrological ruler of the seventh day. The seventh day is the Sabbath. Therefore we’ll call Saturn the Sabbath Planet.” Or what?
(I’m aware that the English day-names are just translations of the Roman astrological day-names, with pagan Anglo-Saxon gods replacing the pagan Roman gods… And I know about how Christians changed the day of worship to Sunday, and in some areas the week is considered to begin on Monday because of that, blah blah blah. I’m not curious about that. I’m just curious about the Greco-Roman vs. Jewish questions above.)