Arnie Cutler wrote: The story as I understand it was that September through December were at one time the seventh through tenth months. At the time of Julius Ceasar the calendar was adjusted to correct an increasingly erroneous match with the seasons. So the months of July and August were added and the names were chosen to honor Julius Ceasar and Augustus Ceasar. Sept.- Dec. were moved down to make room for the two new months.
Yes, And this gave us the so-called Julian calendar with a leap year every four years--which most people think we still use. In fact we have been off that standard for some 250 years (in the US, Canada, and other British lands), and some 400 years in the rest of the world. The astronomers under Pope Gregory noted that by the 1500s the calendar was again off some 11 days by the Julian method, so they invented the Gregorian calendar which we now use. The solar year is not 365.25 days but more like 365.248 days To correct for this, we now skip a leap year once every 100 years. So 1800 and 1900 were not leap years. 1700 was in the states, but not in France. But this overcorrects the problem, so they have to put back in the skipped leap year once every 400 years. Thus 2000 will be not only a leap year but a leap century(?)-- easy to miss. It'll look like a normal leap year on the calendar, but will be a first ever.
But the lesson that could be put to great use in math classes looking for ties to social studies is: Why was our switch to the Gregorian calendar delayed? It is related to the question of why the rest of the world uses metric and we don't. Answer--construct it yourself! but think France, Rome, Church of England. This also helps to date when all of this occurred. Finally, it is also related to the fact that Geo Washington was born, not on Feb 22, 17xx but on February 11. At least, that's what mom's calendar said.