system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How did the current 5 day work week, 2 day weekend come into existence?
gpt
It started with individual companies giving Saturdays off for Jewish workers, but for everyone else, it came from unions.

Before labor unions, you worked every day except Sunday (for church).  As unions became more commonplace, they started negotiating for things like 40 hour work weeks and 2 day weekends.

These were the ideas that got codified into labor laws in use in the US today.