Reprinted from the March 23, 2009 newsletter:
While doing genealogy you will come across challenges with dates. The Julian calendar was imposed by Julius Caesar in 46 BC to fix the previous less accurate calendar that was off by 80 days. Unfortunately, by the late 16th century, the Julian calendar was off by ten days. Pope Gregory created a calendar commission of scholars and ecclesiastics to fix it. On 4 October, 1582 the fix took effect and the calendar jumped ahead ten days. Catholic countries adopted the new calendar but Protestant Europe and the Eastern Orthodox did not. Great Britain and the American colonies didn’t accept the adjusted calendar until September 1752 when people “lost” 11 days to catch up.
Prior to the acceptance of the new Gregorian calendar, almanac printers printed two columns of dates as “English” for Julian and “Foreign” or “Roman” for the Gregorian. When the printers only printed one column of dates in the 1753 almanacs there was a lot of confusion so they reverted back to two columns called “Old Style” and “New Style.” To understand the confusion, consider George Washington. Under the Julian calendar, his birthdate was 11 February 1731, which was late in the year (New Year’s Day was March 25). However, under the new Gregorian calendar, his birthday was 22 February 1732, early in the year because New Year’s Day was January 1. As a result you might find his date of birth listed as 11 Feb 1731, 22 Feb 1732 or 11 Feb 1731/2. For genealogists this causes headaches as people had 11 days added to their birth dates but birth certificates weren’t changed to reflect the changed dates.
In Quaker records until 1752 the first month of the year was March, not January, so any references to the “third month” would have been referring to May. When you see a date as 1720/21 it’s called double dating and refers only to January, February and March and never after 1752. You may also see a date with O.S. (Old Style) or N.S. (New Style) to be more specific. Remember, too, that many European countries made the switch in 1582 but England and the American colonies not until 1752. Russia and Greece didn’t switch until the 20th century.
If you discover that an ancestor’s gravestone says he died 31 August, 1810, age 81y 6m 19 days and you figure back, his date of birth would be 12 February 1729. However, the Vital Records for his town say his date of birth was 1 February 1728, you can account for this discrepancy by the change in the calendar. 12 Feb 1729 NS is 1 Feb 1728 OS.
Clear as mud – right?