Old Dates: The 1752 Calendar Change, Double Dating and Quaker Dates
Why George Washington had two birthdays, what "10 February 1731/32" means, how to read Quaker dates like "5th day of 3rd month," and how to calculate a birth date from an age at death.
Dates seem straightforward, until you research colonial ancestors. Records from before 1752 in Britain and its colonies use a different calendar, sometimes with two years written at once. Quaker records use numbers instead of month names. Gravestones give ages in years, months and days. Here's how to make sense of them all.
Two calendars
For centuries, Europe used the Julian calendar, which slowly drifted out of step with the seasons. In 1582, Pope Gregory XIII introduced the corrected Gregorian calendar, which most Catholic countries adopted quickly. Protestant and Orthodox countries switched later.
Britain and its American colonies switched in 1752. To catch up, eleven days were dropped: 2 September 1752 was followed by 14 September 1752. Dates in the old system are called Old Style (O.S.); dates in the new system, New Style (N.S.).
When the year began
The bigger source of confusion is that under the old system in Britain and its colonies, the legal new year began on 25 March (Lady Day), not 1 January. So a date like 15 February 1731 in the old system falls in what we'd call 1732.
From 1752 on, the year began on 1 January.
Double dating
Because people knew both systems were in use, clerks often wrote dates between 1 January and 24 March with both years: 10 February 1731/32. The first year is the old legal year; the second is the year by the new reckoning. Record such dates exactly as written, with both years. Don't convert them to a single year without noting it.
George Washington is the famous example: born 11 February 1731/32 Old Style, which became 22 February 1732 New Style, the date we celebrate.
Months by number
Because the year started in March, the old month numbers were different too:
- Before 1752, March was the first month and February the twelfth.
- From 1752, January became the first month.
That's why September, October, November and December, whose names come from the Latin for seven, eight, nine and ten, were once the seventh to tenth months. You'll see them abbreviated as 7ber, 8ber, 9ber and 10ber or Xber. Read carefully: "7ber" means September, not July.
Quaker dates
Quakers (the Religious Society of Friends) avoided the names of days and months, which come from pagan gods, so they used numbers instead: "the 5th day of the 3rd month 1740." To convert:
- Before 1752, the first month was March, so "3rd month 1740" is May 1740.
- From 1752 on, the first month was January, so "3rd month 1760" is March 1760.
- "First day" means Sunday, "second day" Monday, and so on.
See Quaker Records.
Other countries
If your ancestors came from elsewhere, check when their country adopted the Gregorian calendar. Most Catholic countries switched in 1582 or soon after; many German Protestant states around 1700; Sweden in 1753; Russia in 1918; Greece in 1923. Records in Orthodox church registers may use the Julian calendar into the 20th century. The difference grew from 10 days in 1582 to 13 days by the 1900s.
Calculating birth dates from ages
Gravestones and death records often give a precise age: "aged 63 years, 4 months, 12 days." To calculate the birth date, subtract the days, then the months, then the years from the death date, borrowing as you would in arithmetic. Free online "tombstone calculators" or date calculators do it for you. Remember:
- The result is only as accurate as the age reported, which the family may have guessed.
- Different calculators handle month lengths differently, so the result can be off by a day or two.
- Record it as a calculated date, and note the source.