More can be written, but you might like the FAQ section "Weeks, weekdays, and weekends". There are a number of aspects touched on: how did the seven-day week arise and get standardized? what alternatives are there? how did names of days arise? how did "week ends" arise?

This is not to discourage discussion. Further questions, data, and debate are always welcome. Since you have a broad question, please narrow in on what you want if you have more questions.