have the days of the week changed in the last 3500 years?
90957
With the Jewish calendar, they started the day at sundown, with the day ending at the next sundown. Their Sabbath or Saturday starts on what is our Friday evening. They had what was called a lunar calendar, 30 day months and 360 day years. Later, the Sabbath day was changed to Sunday by the Church.
285030
About 15,000 years ago.
180148
4.3 years older than it looks now.\n\n300 million years.\n\nJust a baby!
355992
I can't think of a single culture that had a calendar and did not have an approximately 365 day year. It's just something you notice, and it's not really avoidable.
223984
By the 15th century the Julian calendar had drifted behind the solar calendar by about a week, so that the vernal equinox was falling around March 12 instead of around March 20. Pope Sixtus IV (who reigned from 1471 to 1484) decided that another reform was needed and called the German astronomer Regiomontanus to Rome to advise him. Regiomontanus arrived in 1475, but unfortunately he died shortly afterward, and the pope's plans for reform died with him. \n\nThen in 1545, the Council of Trent authorized Pope Paul III to reform the calendar once more. Most of the mathematical and astronomical work was done by Father Christopher Clavius, S.J. The immediate correction, advised by Father Clavius and ordered by Pope Gregory XIII, was that Thursday, Oct. 4, 1582, was to be the last day of the Julian calendar. The next day would be Friday, Oct. 15. For long-range accuracy, a formula suggested by the Vatican librarian Aloysius Giglio was adopted: every fourth year is a leap year unless it is a century year like 1700 or 1800. Century years can be leap years only when they are divisible by 400 (e.g., 1600 and 2000). This rule eliminates three leap years in four centuries, making the calendar sufficiently accurate. \n\nIn spite of the revised leap year rule, an average calendar year is still about 26 seconds longer than the Earth's orbital period. But this discrepancy will need 3,323 years to build up to a single day.
784139
This phenomenon happens every few years and has for thousands of years.
511641
Frank H is right - it's not really that 24 was chosen - more like 12 was chosen.  The division is really arbitrary - the day could just as easily have been broken into 10, 40, or 1667 "hours".  \nMost old systems like that are based on the same numbers - a dozen eggs, a circle is 360 degrees, 12 signs of the zodiac, 12 months in a year, 12 disciples, 12 step program - oops, not that one....
950609
The ancients – I don’t know how far back – noticed that life and the seasons repeated itself on a 365 day cycle.  The stars came back to the same position, the rivers would flood on this schedule.  This is why a year was set at 365 days.
1148865
They wouldn't have changed at all over the past 500 years.\n\nReal progress only happens by merging different ideas.
916656
It didn't quite happen that way.\n\nPeople used the sun and sun dials for a long time before our current system of time. Then they started tracking night-time times with water-clocks and similar things.\n\nBut there weren't universally recognized time systems, or such things as our current standard hours and minutes.\n\nWhen clocks (as we know them) began to be made, there wasn't a universal, world-wide time setting.\n\nMonks created the first machines to measure time, to "sound" the time for their religious rituals. (They didn't have universal standards, but varied by place and religious order.)\n\nAround 1330 he got our standard hour.\n\nTowns started building clock towers to sound time for the town (people didn't have their own clocks yet), measuring time from noon to noon or maybe sunset to sunset (or maybe it varied) in 24 1-hour increments.\n\nMinutes came much later.\n\nI don't know when we started world-wide synchronization.
570602
Back in medieval times the king's income was collected by the Exchequer. It was their decision to divide the year into four parts so that sheriffs could travel to deliver the money without having to carry such large amounts. The dates were chosen as the main feasts closest to each of the quarter year days.\n\nThe accounting periods then ended on Lady Day (March 25), on Midsummer's Day (June 24), on Michaelmas (Sept 29) and Christmas Day (Dec 25). It was tradition that the books would be balanced on 29 September.\n\nMost of Europe changed from the Julian to the new, more accurate, Gregorian calendar in 1582, but Great Britain continued with the old one system until September 1752. By this time the difference had increased to 11 days because the Romans had miscalculated the length of a year from the solar cycle.\n\nThese 11 days were 'caught up' by being removed from the calendar altogether in 1752 when 2 September was followed directly by 14 September. In order not to lose 11 days' tax revenue in that tax year, the tax authorities then decided to tack them on at the end of the Christmas period, changing the collection date to 5 January. 80 years later, in 1842 the beginning of the tax year was moved to Lady Day, 6 April and has not changed since.
937907
Approximately 5,000,000,000 years
622119
Although the ancient egyptions had a calendar that was divided into 12 months of 30 days, the current 12 month calendar has been in place since Feb 24, 1582.\n\nSee the page below.
399938
It's all arguable was to when it was written. Western scholars dated the time within the time frame of the date given by archeologist and historians of Europe at the time which were fixing all time to fit within Western thought (thus the begining of the world was with the Garden of Eden and there was a year already established that this occured...therefore all other dates that differed from this had to be changed....sadly while most of the Western world has updated its dates, the eastern history is still not been changed in most reference books....and eastern civilizations are very old and to account for this, because Western science says that all civilization began in Egypt and Mesopotamia...and then of course with the Garden of Eden...the dates of eastern civilizations again have been changed and are still not fixed). Thus some say that the Vedas were written down in 5000BCE, some 1500BCE, some in 500BCE, some in 500AD. Basically, it's all still being debated, but atleast scholars now acknowledge that the Rig Veda is the oldest sacred text and ancient literature in existence. That atleast has been agreed upon. Otherwise, just remember when reading anything about eastern religions that the dates will vary. If you speak to easterners who have retained their tradition telling of the time it is usually much closer to what is believed to be accurate (like the birth of Buddha, etc) than what Western scholars currently have set.
646825
It depends on which calendar you are using, and if you calculate in the adjustments for variations in earth's rotational speed.\n\nIn my world it's Friday May 26, 2006 at approx 1:10 PM\n\nand I'm not sure.
32392
yes, in a way it already has.\n\nthere is a missing day in the history of the world.they went back an did all there cauculations and found there was.\n\nin the Bible there is one part were Jashua is fighting an he asks God to make the sun an moon stant still.\nand He did until they won.\nanother place a man was asking God if he would live to be older, an as a sign , the shadows would go backwords for a certain amout of time.\n\ntheologists have found that the time in both of these incodents have added up to exactly 1 day.\n\nCoincedence?
842314
When there was a conversion from the Julian calendar to the Gregorian calendar, there had to be a change made to account for the year being out of synch with the actual seasons.  The Julian calendar accounted for a solar year equivalent to 365.25 days, but it is closer to 365.2422 days.  As a result, we were adding too many days.  The Gregorian calendar instituted a change where 3 out of every 4 centuries would *not* be leap years.\n\nThe reform happened in 1582.  Ten days were omitted from the calendar, and it was decreed that the day following (Thursday) October 4, 1582 (which is October 5, 1582, in the old calendar) would thenceforth be known as (Friday) October 15, 1582.\n\nThe Gregorian Calendar was adopted immediately upon the promulgation of Pope Gregory's decree in the Catholic countries of Italy, Spain, Portugal and Poland, and shortly thereafter in France and Luxembourg. During the next year or two most Catholic regions of Germany, Belgium, Switzerland and the Netherlands came on board. Hungary followed in 1587. The rest of the Netherlands, Denmark, Germany and Switzerland made the change during 1699 to 1701. By the time the British were ready to go along with the rest of Europe, the old calendar had drifted off by one more day, requiring a correction of eleven days, rather than ten. \n\nThe Gregorian Calendar was adopted in Britain (and in the British colonies) in 1752, with (Wednesday) September 2, 1752, being followed immediately by (Thursday) September 14, 1752.\n\nI think this must be the year that you are referring to... 1752.