The Reason for Double-Dating

According to the Julian Calendar (which was used by the Pilgrims), the New Year started on March 25, not January 1.  It also declared that a year was 365 days, 6 hours long.  However, in 730 AD, the Venerable Bede, a monk, discovered that this calendar was off by 11 minutes and 14 seconds. Nothing was done about it, however, and over the next 850 years the calendar kept getting further and further off until it was nearly ten days off in the year 1582. Pope Gregory XII declared in 1582 a new calendar would be used, named the Gregorian calendar, which would fix the problem.

However, much like the metric system and the United States today, people were resistant to logical change. The new calendar was adopted immediately by France, Italy, Spain, Portugal and Luxembourg, and within a few years by Germany, Belgium, Switzerland, and the Netherlands. But it wasn't until nearly 200 years later that the calendar was adopted by the British government (and thus the American colonies).

The British Parliament decreed that September 3, 1752 should be renamed September 14, 1752, which would fix the eleven day discrepancy; and further, they ruled that January 1 would be the beginning of the new year--it would no longer be March 25. The Russian Orthodox Church, and several mid-east countries are still using the Julian calendar even today. The Julian calendar is nearly half a month off now.

To make matters worse, while dates in the 1700s are 11 days off, dates in the 1600s are just 10 days off.  So, when the researcher goes looking at records written in the 1600's, they will find the dates are by the Julian calendar, not our present-day Gregorian calendar.  To note this, many times the date is written 1 March 1692 (O.S.) which stands for "old style", or 11 March 1693 (N.S.) which stands for "new style".  Other sources, such as this web page, will simply write that same date as 1 March 1692/3, to indicate it was 1692 to them, but 1693 by our present-day calendar.  Of course, this does not take into account the ten days the calendar was off, so the date is also sometimes written like 2 March 1692 / 12 March 1693.  

For a more detailed explanation on the calendar differences, I refer the reader to an article titled "Old Style vs. New Style" in The Mayflower Descendant, 1:17-23.

Beginning in 45 B.C., many parts of the world used the Julian calendar to mark the passage of time. By the Julian calendar, March 25 was the first day of the year and each year was 365 days and 6 hours long. In 1582, Pope Gregory XIII determined that the Julian calendar was incorrect: each day was just a little bit too long and the human calendar wasn't keeping up with nature's calendar. To solve the problem, Pope Gregory XIII created what is known as the Gregorian calendar. This new calendar changed the first day of the year to January 1 and also jumped ahead by 10 days to make up for the lost time.

The practice of double dating resulted from the switch from the Julian to the Gregorian calendar. Not all countries and people accepted this new calendar at the same time. England and the American colonies didn't officially accept it until 1752. Before that date, the government observed March 25 as the first of the year, but most of the population observed January 1 as the first of the year. For this reason, many people wrote dates falling between January 1 and March 25 with both years, as in the following examples.

By the time England and the colonies adopted the new calendar, the discrepancy between the calendars was eleven days. To resolve the discrepancy, the government ordered that September 2, 1752 be followed by September 14, 1752. Some people also added 11 days to their birth dates (a fact which is not noted on their birth certificates). You should also watch for dates that are recorded as double dates even after all calendars had officially switched. People sometimes accidentally wrote double dates.

Marriage Banns and Intentions

Church records often list the date on which a couple makes the announcement that they intend to marry. These are called marriage banns. In addition, you can find marriage intentions, which were non-religious public announcements of the couple's intention to marry. Don't misinterpret the dates of marriage banns and marriage intentions as the actual wedding date.

Death and Burial Dates

Church and cemetery records often contain the date of the funeral in addition to the date of death. Don't confuse the burial date with the date of death.

Date Formats

When you look at records from other countries, you should be aware of the date format that they use. In the United States, we normally write dates with the month first, the day second, and the year last. For example, we write October 15, 1970 as 10/15/70. However, many other countries reverse the order of the month and day. They write October 15, 1970 as 15/10/70. Since there are only twelve months in the year it is often easy to tell which date format was used because one of the first two numbers is greater than twelve, as in the example above.

If neither of the first two dates is greater than twelve, it is harder to tell which format was used. For example, April 3, 1970 can be written as both 4/3/70 and 3/4/70. If you run into this problem, take a few moments to look at other dates in that group of records. You should eventually run across a date where one of the first two numbers is greater than twelve, and then you'll know the answer to your question.