Most of the history/theory I was going to share has been covered, but I’ll add that having a week of ~7 days is probably based on human biology. I think it’s a historical accident that the Jewish 7 day cycle beat out the Roman 8 day cycle, but I don’t think it’s a coincidence that we have this cycle.
A friend had cancer and needed chemotherapy. And she was put on a 7 day schedule. At first she was upset, and felt that the convenience of the medical staff was taking precedence over her health. But she said, after a couple of cycles, she realized that she NEEDED the downtime on the weekend.
Pushing it back before farming, how long does fresh meat last without some form of preservation or refrigeration? Perhaps seven days is the longest a hunter can go between kills without getting hungry.
As others have noted, being tied to lunar phases seems to be perfectly logical. See the wiki I linked upthread.
A week of five, six, or seven days makes perfect sense for keeping up with a lunar calendar. Throw in the natural split between New and Full and six is right out (but you could still make a case for five or seven). If the choice is between those two, then I could see it coming down to trade and economic activity (one in five days requiring some special observance versus one in seven).
Coming back to the OP, there are some local aberrations. A prime example is the Philippines (mentioned by another poster in the thread I linked to; meanwhile I read up more on this).
Until 1844, the Philippines were on the “American date”, which is pre-20th century speak for lying east of the international date line - Philippine clocks ran behind European clocks by a number of hours based on the difference in longitude. This was because, under Spanish rule, the Philippines were administered from Mexico and had their most important trade routes to Acapulco, so the American date made sure the calendar in the Philippines was aligned with those in the ports with which they traded. Other islands in the immediate vicinity of the Philippines were on the “Asiatic date”, though, i.e. west of the international date line. This meant that the calendar of these islands was ahead of the Philippines by one day.
In 1844 it was decided to change that and to align the Filipino calendar with that of the neighbours. To accomplish that, 31 December 1844 was dropped; Monday 30 December 1844 was followed immeditately by Wednesday 1 January 1845. So here you had a re-setting of the cycle of weekdays, unlike in the case of the 1582 Gregorian reform.
That’s very dependant on local temperatures. I’ve had meat go back overnight in the summer.
I think it’s highly unlikely that hunter-gatherers expected to eat meat every day, however, so even if “7 days to rot” made sense somewhere, I would be surprised if that’s what drove the weekly cycle. Except in the arctic, most “hunter gatherers” are really “gatherer hunters” by calories consumed and also by time spent obtaining those calories.
Also, the week seems to have arisen with agriculture, and not be a thing hunter-gatherers did. The most plausible explanations for its start all trace it to regular “market days”, which is a feature of fixed settlements. (Hunter gatherers sometimes have an annual or couple-time-a-year festival where different groups come together to trade and to find spouses for young adults. But not usually weekly things.)
There was a similar adjustment when Alaska was sold by Russia to the US. Except there they had to do both adjustments, Julian → Gregorian and moving to the other side of the dateline. Because of the latter, they actually repeated a day of the week.
It was on 18 Oct 1867 (Gregorian), which Google tells me was a Friday. So sorry about your theory not holding up to reality.
One other thing about the calendar and the purchase. At the time the Julian calendar was 12 days off the Gregorian. However, they only skipped 11 days when they switched. That one day difference was also because of moving to the other side of the dateline.
I also forgot about a more recent moving of the dateline. In the 1990’s, part of Kiribati moved from the American side of the line to the other side. That would be the same move that the Philippines made, so they also skipped a day of the week.
No, it wasn’t. Turns out that there have been a couple other cases of dateline shifting and of course Wikipedia catalogs all of them, including giving days of the week. The only one involving a Tuesday was the one Schnitte gave above for the Philippines in 1844.
According to Wikipedia, “week”: A continuous seven-day cycle that runs throughout history without reference to the phases of the moon was first practised [sic] in Judaism, dated to the 6th century BC at the latest.
All fascinating stuff! This OP thanks you for your info. I am impressed that this sequence seemingly has been without interruption or correction for 2.5K years or more.
