It’s not a quick thing to define the date on which Easter falls in a given year in the Western tradition. My understanding has long been “the first Sunday after the first full moon following the vernal equinox.” That appears to be largely correct, except that unconventional definitions for both ‘full moon’ and ‘vernal equinox’ are being used–“fourteenth day of an ecclesiastical lunar month” and “March 21,” respectively, regardless of when the moon really reaches fullness or when exactly the equinox occurs.
This odd definition may contribute to the fact that there’s not any sort of easily discernible pattern to when Easter happens. That doesn’t mean that there aren’t mini-patterns, however. If one examines the data over, say, a six-hundred year period, one picks up on a semi-regular event: the same date will be Easter three (or four) times over twenty-two (or thirty-three) years, with eleven years between each occurrence. To give three examples we’re currently experiencing, there’s 1991-2002-2013-2024 for March 31; 1999-2010-2021 for April 4; and 1995-2006-2017-2028 for April 16. A fourth such mini-cycle ends today: April 12 was Easter also in 1998 and 2009.
Ninety years ago today, my mother was born. Were she still alive, this would be the fourth time she got to celebrate the start of another year on Easter. The first was her 6th, back in the middle of the Great Depression. Yes, that’s a sixty-two year gap between April 12 Easters, but that’s actually shorter than the upcoming one–the next time Easter is to occur on this date is in 2093.
I was the tiniest bit surprised to discover that prior to 1998 she hadn’t celebrated her birthday on Easter in my lifetime—I guess I’m simply recalling some gauzy sensation from my youth of the two events occurring very close in time. Martha looked for pictures from that day but didn’t find any (also a mild surprise, given how much of a shutterbug she is). We do have evidence from 2009, when Mom turned 79, though:
Other pictures capture the cake Dad had gotten from an excellent local bakery and of Mom displaying one of her gifts from us (a memoir by a fellow who worked on her parents’ farm when he was growing up, about his experiences running cross-country in high school and college–I brought it home with me after clearing out the folks’ townhouse; while writing this up, I was able to immediately find it on the bookshelf where it currently resides). There’s also a photo with both Mom and Dad in it, taken right after she successfully blew out her candles.
A lot sure can happen in eleven years.