Julian and Gregorian Calendar

Photo by Waldemar Brandt on Unsplash

​Many who have midwestern pioneer ancestors feel fortunate to trace them back to the early 1800s.  If you cross the pond, you may find yourself running into the timeframe of the Julian to Gregorian Calendar.  I was fortunate to have had someone knowledgeable guide me when my Luxembourg ancestors had key dates during that transition time.  Unlike then, now there are many resources online to guide you.  Let’s look.

​The change from the Julian calendar to the Gregorian calendar came about because by 1582 the calculations made for the Julian calendar over time resulted in an extra ten days, skewing church holidays into different seasons. To make matters more complex, the proposed calendar was not adopted at the same time throughout the world.  Because the Gregorian calendar was proposed by the Pope of the Catholic Church, it was viewed with suspicion from Protestants.  The Civil Calendar was not controlled by the church and civil officials determined if/when it was adopted. FamilySearch has an excellent article and chart that helps you to determine when the Gregorian calendar was adopted in the country that you are researching.  You can also view a chart of countries that shows when they stopped the Julian calendar and the date, they started the Gregorian calendar on Ancestor Search.
 
For an even more detail account of the introduction of the Gregorian calendar, check out this article on Wikipedia.  Familypedia has additional details including the history behind the naming of the months.
 
This can be brain overload, but it is good to have an awareness that dates might not be as expected because of the changes.  If you have colonial ancestors in American, then you’ve likely are aware of these calendars. Nick D’Alto has an excellent article on Family Tree which explains why you should care about this calendar change.  He also notes a converter you can use to calculate the old Julian date to Gregorian date.   As an example, the date of May 1, 1770 is May 12, 1770 in the new style. Unfortunately, you cannot assume the date is moved 10 days forward in the Gregorian system.  Adjustments are made across the centuries and converters like these save us the need to calculate.
 
After exploring the Julian and Gregorian calendars, you will be ready to imagine how confusing this change must have been across the world, to our ancestors and current day genealogists.   We are halfway through January…how are those genealogy goals?  Be glad you do not need to adopt or invent a new calendar!