Good question, I actually had no idea either so I did some research on it and this is what I got: It was Roman emperor Constanstine in 321 A.D. who first established the 7 day week in the Roman Calendar and designated Sunday (for Sun's day) as the first day of the week. Monday -- Moon's day Saturday - Saturn's day Some of the Roman names are still used but the other days are named after Anglo-Saxon words for the gods of Teutonic mythology: Tuesday - Tiw's day (god of battle and victory) Wednesday - Woden's day (father and ruler of the gods and mortals) Thursday - Thor's day (god of thunder) Friday - Frigg's/Friia's day (wife of Odin, great mother of the gods)

hello, your question is in general i guess and you get a bit particular answers. normally it comes from mithology in european languages, specially, those ingfluenced by roman politics. that's why you get those explanation above. but not everywhere you find the same reasons or mithology, yes, most romanic and germanic languages reflect roman gods (those who were part of dayly worship, if in medieval times they looked for more sophisticated explanation is due to the thoughts of the time), but portuguese use first day, second day and so on. Russian have a different set of dedications, which i can't explain. turks and persian share a bit of commonground, arabics have another. and if you look for it you may find different motives for different cultures and times (i mean periods of history).

It depends on the language obviously. For English, I can tell you only about those which are the same in Italian and French: Sunday (ok, it's Domenica here meaning Day of God, but you know the Sun represents God), Monday and Saturday. Philosopher Boëtius (470-525 A.D.), as it was pretty a trend at those times, matched the 7 planets of the now-called Solar System he knew with the 7 notes, starting from the Moon (that he considered a planet) for it was the closest to Earth: Moon – D Mercury – C Venus – B Sun (not actually a planet, but Boëtius thought it moved around Earth anyway) – A Mars – G Jupiter – F Saturn – E Then, putting the notes in order so that they were constantly separated by a rising "fourth" tune distance [you need to know musical notation a bit at least to understand this; and I might have translated it from Italian improperly though], he obtained this sequence: D G C F B E A, corresponding to Moon, Mars, Mercury, Jupiter, Venus, Saturday, Sunday. In Italy and France (as well as in other countries) the week days are named as: Moon-day (lunedì, lundi) Mars-day (martedì, mardi) Mercury-day (mercoledì, mercredi) Jupiter-day (giovedì, jeudi) Venus-day (venderdì, vendredi) Saturn-day (sabato, samedi... however this two rather come from Hebrew "Sabbath" most likely) Sun-day. As Rochelle wrote, the English (and German) week days get their names from Nordic mythology – those, I really don't know who chose them and their order. Hope this helps anyway. ;)

To add a little more - the word "week" comes from the German word meaning "change" - refering to the changing phases of the moon. Actually, the Chinese names for the weekdays is the most logical - Monday is "xing qi yi" (week one), Tuesday is "xing qi ar" (week two), etc. The only one that doesn't fit the pattern is Sunday - "xing qi tian", which means week day. Six out of seven isn't bad.