Everything in our societies is structured on it. The system of identifying every new day by a standard name stretches back centuries, and as you can guess, Greeks’ fingerprints are all over it.
In those ancient times, there was an astrological idea that the planets ruled the day. It therefore made a lot of sense to name the days after the planets and the gods.
Saturday is Saturn Day. Sunday is Sun Day. Monday is Moon Day. Tuesday is Mars Day. Wednesday is actually spelled so funny because it is Woden’s Day and Woden – the creator of the universe. Thursday is Thor’s Day and Friday is Venus Day.
This video is quite informative.