One of the most important aspects of performing family history research is accuracy. You’ve probably read it over and over when reading how-to articles: record all of your sources, and for heaven sakes, get the dates right! But when it comes to dates, is it always so simple? It is actually a more complicated subject than you might think. Our methods of dating events have changed over the years, and there are regional differences even today. It is helpful, then, to learn a little bit about our “dating history” before we delve into further research.
A LITTLE HISTORY, PLEASE!
You may vaguely have some awareness that once upon a time, there was an Old Style Julian calendar, and that somehow, we came to use a New Style Gregorian calendar. But how did this come about? The Julian calendar was introduced in Rome in 46 B.C. and into the Christian world in 325 A.D. This calendar assigned each year 12 months and 365 days, with a Leap Year of 366 days occurring every four years. You might think it sounds a lot like our current system, because it is. However, it became clear the Julian calendar was, over time, falling behind the sun’s natural calendar. Each day was a few minutes too long, resulting in a loss of three entire days over a period of 400 years. By the time the year 1582 rolled around, the world had lost ten days. This loss affected the Church’s calculation of the date of Easter. In March, 1582, Pope Gregory XIII altered the calendar in order to more accurately follow the sun. In order to make up for the lost ten days, he made the day after March 4, 1582 into March 15 instead of March 5. In addition, the Pope made a few other changes. He omitted three Leap Year days every 400 years, so that the loss of three more days could be prevented. To accomplish this, he chose those years ending in “double zeroes”, the ones that mark the division of the centuries. The rule that was developed made those double-zero years that can be divided evenly by 400 into Leap Years (1600, 2000.) Those double-zero years which cannot be divided evenly by 400 will not be Leap Years (1700, 1800, 1900, etc.)
Another change made by the Pope concerned New Years’ Day. Before, New Years’ Day fell on March 25. However, after 1582, New Years’ Day would be celebrated January 1, just as it is today.
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