Calendars make a difference in research results

One change here in Utah is that I have to get used to daylight savings time again. Arizona is one of the few places in the United States that stays on the same time all year round. So, I have a hard time with changing twice a year. Just think, as genealogists we have all sorts of times and dates to consider. It is not unusual for researchers to have to deal with multiple calendars. Here is a list of a few of the calendars you might encounter:

The Julian to Gregorian Calendar changes
The French Republican Calendar
The Hebrew Calendar
The Revised Julian Calendar or the Meletian calendar

There are dozens of different calendars that have been used in different parts of the world at different times. The short list above includes the ones you would most likely find in your research if your ancestors came from Europe. If your ancestors came from an Asian country such as China, you would have to adapt to the Chinese calendar. The effect of all these calendars the historical changes in the use of one or another is that the dates you find in records may have to be translated into our modern calendar to make sense.

Why do calendars matter? The best way to answer that question is to look at an example of the date changes. What if I were doing research in France and ran across this "date?" 2 Messidor VIII. First of all, would you even recognize this as a date? What would your current genealogy program do with the date if you entered it as it is? By the way, here is what the FamilySearch.org Family Tree would do with that date:

OK, so depending on the program, the date could be left as it is or translated into the current version of the Gregorian calendar. Here are some programs for translating dates in the various calendars.

The French Revolution Calendar http://www.windhorst.org/calendar/
Julian to Gregorian and Gregorian to Julian http://stevemorse.org/jcal/julian.html
Hebrew to Gregorian and Gregorian to Hebrew https://www.hebcal.com/converter/
Revised Julian Calendar http://www.calendar-converter.com/julian/

If you run into another calendar system, it is highly likely that there will be a converter on the internet. For example here is the Mayan Calendar Converter:

https://maya.nmai.si.edu/calendar/maya-calendar-converter