Why in almost every calendar of different culture, a week consists of seven days? Are there any link between different calendars?


The Ancient Greeks and Egyptians had a week of 10 days, the Ancient Romans of 9, the Aztecs of 5 days, the Ancient Japanese of 6, the Ancient Chinese week went from 9 to 12 days...

The Babylonians started the week of 7 days, pairing the "planets" they could see (Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn) to the lunar month of 29 days. So they made it 4x7= 28 days and at the end of the year they had special weeks longer than 7 days.

  • 1
    Sources would greatly improve this answer. Aug 6 '17 at 11:33

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