The Modern Calendar Week and How it Got that Way

You may have heard this before: the days of the week are named after heavenly bodies, in whatever Roman language you choose. Sunday for the sun; Monday for the moon; Tuesday for the war god Tiw (or, in many other languages Mars); Wednesday for Woden -- more popularly know as Odin -- or his fellow psychopomp, Mercury; Thursday for Thor or fellow thunder god Jupiter; Friday is for Venus; and Saturday for Saturn: curiously the only one that retained its Greek namesake in English rather than adopting the Norse equivalent. Jump from one planet to the next in that order however, and you'll notice a puzzling phenomenon: the names appear to be in no particular order. Many etymological texts will brush this off as a "complicated mathematical relationship"; the truth is in fact somewhat mathematical but not that complicated.

First, recall that ancient man believed earth to be the center of the universe. (This is excusable: everything does appear to orbit it, albeit with subtle 'epicycles' you'd never notice without careful observation.) Given the fact that they remain confined to ever-increasing portions of the night sky, one can conclude that, according to the geocentric theory, the order of the heavenly bodies, from farthest to closest is: Saturn, Jupiter, Mars, Sun, Venus, Mercury, moon. Notice that, starting on any day of the week, you can get the days of the week in their proper order by jumping over two names and landing on the third, wrapping back to the beginning whenever you reach the end: Saturday, Sunday, Moonday, Marsday, etc. But why would you skip to every third name?

The ancients were in fact skipping to every twenty-fourth name. Having divided the day and night into twelve hours each (believing six to be a sacred number and twelve doubly so) , the assigned each hour to the tutleage of, and worship of, each god in turn, confining their affection to those important enough to share a name with a heavenly body. It is a simple pattern of counting aloud while pointing at each name in turn (or, as a mathematician would, finding the modulus of twenty-four with respect to seven, that is, the remainder when twenty-four is divided by 7) to confirm that if one day starts with Saturn's hour, the next day will start with Sun's hour and so on: hence, Saturday, Sunday, etc. It is worth remarking that only cycles through all the planets because seven and twenty-four have no common factor: had the ancients not included the moon among their count, each day would start with the same god's hour -- perhaps the sun, or Saturn -- and would have to look elsewhere for its name. Had the ancients been unable to see Uranus with the naked eye, then only four of the eight celestial bodies would ever come up first; we would have a four-day week and four planets that never got a chance to open.

Finally, those who specialize in such things can draw fairly convincing parallels between the account of the seven days in Genesis with the temperaments and specialties of the seven deities invoked by pagan names. This suggests an intriguing interplay between the Middle Eastern religions that influenced, and ultimately became, ancient Judaism and ancient Olypianism. Which way the lines of influence run is open for debate, but it is apparent that we owe our seven-day week, eclectic order and all , to seven wandering lights in the geocentric sky.