How and who came up with seven days in the week?
…before Christianity cemented it into our culture. The sabbath, the seventh day of rest and worship certainly cemented the seven day week into our culture as Christianity spread across the globe and became the foundation of so many of the worlds dominant cultures. But from there you will get some confusion. Many references will mention the seven visible heavenly bodies (Sun, Moon and planets) as the source of seven days, these certianly were the sources of our current names, but the real source probably lies a lot further back… It may be that the phases of the Moon are the ultimate source. The moon has a 29 day cycle of phases giving rise to natural calendrical clock hanging in the sky for all to see. A 29 day cycle would be a bit long