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). See the links below for more detailed information.

 

Books, articles, CD's, Software, Tapes etc.
On the Web.

Books

Smith. Genealogical Dates: A User Friendly Guide 1994 (find in a library)

Webb. Dates and Calendars for the Genealogist. 1989 (find in a library)

Articles and Chapters:

D'Alto/ "Save the Dates" Family Tree Magazine November 2007 pp. 42-45

Jacobus. Genealogy as a Pastime and Profession Chapter 18: "Dates and the Calendar"

Prindle. "The 1752 Calendar Change" in The American Genealogist October 1964 pp. 246-248

Remington. Quaker Preparation for the 1752 Calendar Change" in NGS Quarterly June 1999 pp. 146-150

Rubicam. Pitfalls in Genealogical Research Chapter 4: "The Problem of Dates" and Chapter 5 "The 1752 Calendar Change"

Sperry. "Time to Take Note: The 1752 Calendar Change" in Ancestry Nov. /Dec. 2000 vol. 18 no. 6 pp 30-33

Sperry. Reading Early American Handwriting. Chapter 6: "Dates and the Calendar Change."

Tapes

. Born When? Dates As Genelogical Tools by Patrica Law Hatcher Recorded 9/12/2001 at Great River Bend
 
Dates in Genealogy - Beyond Month, Day, Year by Patricia Law Hatcher Recorded  8/7/2002 at California - A Goldmine of Diversity
  
 THE CALENDAR AND GENEALOGY IN THE BRITISH ISLES AND THE AMERICAN COLONIES  by MARILYN MILLER MORTON  Recorded 10/15/1994 at On to Richmond

The Dating Game or Making the Calendar Work for You  by David Dumas Recorded 10/22/1998 at The Fifth New England Regional Genealogical Conference

 TIME FOR GENEALOGY: CALENDARS, DATING SYSTEMS, LEGAL AGES AND OTHER TIME CONSIDERATIONS by ERIC G. GRUNDSET
 Recorded 6/1/1994 at Exploring a Nation of Immigrants - Houston Style

 EVOLUTION OF CHRISTIAN CHURCHES IN THE U.S., WITH COMMENTS ON THEIR RECORDS AND INTERPRETATION OF JULIAN CALENDARY DATES  by WILLIAM C. KLEESE  Recorded 5/3/1995 at A Place to Explore

Software

First, check the genealogy recording program to see if it offers a calendar with date calculating functions. Many have this feature.

GenDate Converter (I've not tried it)

Calculating dates:

Calculating when you know the age at death: calculator1 * calculator2 * rule of 8870
* Date of Birth from Tombstone
* Day of the Week Calculator (scroll down)
* Rose-Ann Bray's chart for calculating birth year based census information.
* Skillbuilding: Date Calculations

Estimating dates:

*Approximating birth dates
* Good Connexions: Estimating Birth Dates (England and Wales)
* Pack. Estimated dates
* Approximating dates

Historical dates:

* Dates
* Calendar Change
*Genealogy in France: Republican Calendar
*Good Connexions: Time Travel
* Rubincam (excerpt): Calendars
* Smith. Speaking of Dates!
* Spathaky. Old style and New Style Dates and the Change to the Gregorian Calendar -- a summary for genealogsts.
* Sperry. Time to Take Note: The 1752 Calendar Change.
* Sperry. The Complexities of Leap Year
* Sperry. When is George Washington's Birthday
* The French Revolutionary Calendar
*Old style to New Style: calculator1
* Quaker Dates
* Understanding Quaker Dates (same as above)
U.S. Gen Web Old Calendar and Dating Information

Calendars and Date converters:

Find the day of the week and links to events in the world at the 10,000 Year Calenda. At that same website you can calculate the number of days between dates or add or subtract years, months and days from a given date.

Here is another date calculator

Sometimes you have the month and day... but not the year. Find the years in which the particular day/month occured to make a more educated determination of the year.

You can create and print out a calendar for any year -- a useful tool if you are working with a diary or other sources that document events in an ancestor's life.

Sometimes dates and other numbers are written in roman numerals and not all of us remember how to covert, so you may find this Roman Numeral and Date Converter to be helpful. If you want it explained, read this conversion guide.

More links:
Cyndi's List: Calendars & Dates

Return to Bobbie's Genealogy Classroom.

This page last updated October 7, 2007