Your Guide to Genealogy and Dates

The careful genealogist pays a great deal of attention to dates. One of the first things we must learn is how to properly record them to avoid ambiguity... e.g. 9 Jan 2005.

We must learn how to calculate when we know a person's date at a specific age. We need to be aware of reasonable estimates and when to recognize that a date doesn't fit. For example, it is unlikely that a person lived 136 years or had a a baby at 67-- yet some genealogies have dates that indicate this is so.

We must know about calendar changes. The one that most commonly foils American researchers is the calendar change in 1752. In brief, prior to that New Years day was March 25 and the year did not change until that date. When the calendar changed to a January 1st new year, accomodations had to be made in the way dates were written to avoid confusion. Dates were designated O.S. (old style) and N.S. (new style).

There are some handy date converters for us on the internet that will allow us to determine a more exact date with incomplete information.

See the links below for more detailed information.

There are actually two books written on the subject of what the genealogist must know about dates!

Recording dates

Genealogists record dates in a very specific way: 07 February 1898. They also specify if a date is approximate, using standard abbreviations for circa (about), between, after and before. Learn how to do it right with this lesson: Recording Dates.

Calculating dates:

Calculating birthdate when you know the age at a given time. It's not as simple as just subtracting!

Estimating dates:

The 1752 Calendar change (Julian to Gregorian) declared January 1 to be the first day of a year, instead of March March 25. This causes complicatons for genealogists, who will find dates for the months of January, February and March recorded as being in one of two years, e.g. 7 January 1701/02 This is referred to as double dating; the first year being O.S. (Old style) and the second year N.S. (New style). Learn more with these links below.


Calendars and Date converters:

Want more links on this subject? Where else!? Cyndi's List Calendars and Dates

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This page last updated September 30, 2011