When did we start having work weeks and weekends? When did weekends become only two days and has there ever been a civilization/economy that has more than two days off for the weekend?

in modern history it's always been common to have at least one day off, depending on the dominant religion in the area, for worship. that day would be friday for muslim, saturday for jewish and sunday for christian people.

in the early 1900's Ford started giving both saturday and sunday off because of that, which slowly trickled into other industries as well. during WW2 certain changes in the law changed the amount of hours set for a working week. it became 42 hours I believe. then taking in account the most widespread religions, it was the most practical to go for saturday and sunday as days off. and that's slowly developed to become the international system for a working week. for the brief period between ford and the legislation, there probably were diverse areas with all three major religions heavily represented. they might have had a three day weekend for a while, but that's not statistically significant.

however, historically speaking, there was no defined amount of hours per week, so people would just systematically have one day off for worship, as said, for the dominant religion in the area. having more days off than that wouldnt be practical for the people running businesses. prior to the arrival of industry things were a lot more sketchy than that, and people would often just be put to work depending on when the work presented itself. they just didnt have the luxury of being able to systematically give them the same days off every week, and saw no reason why they should.