Groups of Jews not from shevet Levi would work in the bes hamikdash, a week at a time. Their primary responsibility was attendance: being present when korb'nos tzibur, public offerings, were brought. ...
I was taught in yeshiva that as a young man, Rambam just studied Torah and was supported by his brother, who was a jewel merchant. Then his brother died at sea, so Rambam became a physician. Recently ...