Yesterday was February 29, Leap Day, which, as we all know, happens every 4 years. Have you ever wondered why there’s a leap day at all, and why it’s 4 years and not, say, 7?
In 1582, then Pope Gregory issued a new calendar to be used by the Christian Church in Europe. Due to the differences between the then current Julian calendar, the solar year, and the lunar year, the dates for the Easter holiday had been inconsistent for some time and Pope Gregory wanted to change that.
Easter was calculated to fall on the first Sunday, following the first full moon, after the vernal equinox (the first day of spring), which had always been around March 21st. It was known that the length of the solar year – the time between two vernal equinoxes – was actually 365.25 days, not an even 365. However, the more precise length of time between vernal equinoxes is really 11 minutes shorter.
This discrepancy meant that, after many centuries, the vernal equinox was occurring about 10 days earlier than March 21st. Consequently, the date for Easter (and everything else) kept moving further back in the calendar because the date of the vernal equinox kept moving – slowly, but still moving.
Pope Gregory’s new calendar added one day to February every 4 years to make up for the approximate ¼ days not accounted for in the Julian calendar. Since 1583 this has fixed the date for the vernal equinox at, or as close as possible to, March 21st, and has given us what we now call the Gregorian Calendar.
Following February 29 we come to March and that famous line from Shakespeare’s Julius Caesar: “Beware the Ides of March!” Well, what is an ‘Ides’ anyway?
In the Roman calendar the ‘Ides’ of a month referred to the middle, or half way point, of the month. That day was actually the 13th day for most months, but was the 15th day for March, May, July and October.
The ‘Kalends’ (taken from a Greek word, hence ‘calendar’) was the name for the 1st day of the month. The ‘Nonnes’ was the name of the 8th day before the Ides. It was called Nonnes, ‘the ninth’, because using the Ides as day 1 and counting 8 more days gave you the day.
Other days of the month were referred to by counting back from one of the 3 days, and you counted the named day as ‘day 1’. For example, March 3rd would be ‘the 6th day before the Nonnes of March’ and so on. It’s kind of strange for us to think about dates in the last two weeks of a month like that – March 20th wasn’t ‘the 6th day after the Ides of March’, but rather ‘the 11th day before the Kalends of April’ – but that’s how it went.
Oh those nutty Romans. Imagine doing this kind of thing in Latin too – ugghh!
Check out the following titles for more crazy calendar conundrums – if you have ‘the time’ that is!
Leap Day: A Novel
Leap Day by Wendy Mass
Taylor is only 4 years old…but she’s getting her drivers license? Born on February 29, she is now 4, or 16 if you prefer, and getting her license is only one way she plans to celebrate.
Mapping Time: The Calendar and its History
Mapping Time by E.G. Richards
The Dance of Time by Michael Judge
- Calendar by David Duncan
Filed under: CLP - Lawrenceville, News & current events, Teen Interest | Tagged: Calendars, Leap Day, Shakespeare | Leave a comment »