top of page
If you enjoyed this article, please consider supporting my work.

Old Style Dates - Times have changed

Updated: Feb 15, 2021

One thing I learned during my research is that “times really have changed”. The old cliché has a more literal meaning than many people realize. The calendar as we know it has a very interesting past.

Why is this important?

In old town records, church records, tombstones, epitaphs and written genealogies, dates were sometimes written as “1st month”, “2nd month”, etc., as opposed to writing out the name of the month. It seems reasonable to assume that when a record says “on ye 12th day of ye 7th month in the year of our Lord 1743” it is referring to July 12, 1743, however, this assumption would be incorrect.

Today we consider the first month to be January, however, this was not always the case. In ancient times, the new year was marked by the Equinox which was observed, twice a year when for just a moment, the center of the sun is aligned in the same plane as our equator. Today this occurs between the 20th and 21st day of March and again on the 22nd and 23rd day of September. So, according to the equinox the first month was actually March.

The Julian calendar was made in 45 B.C., under the reign of Julius Caesar, the Equinox was fixed to the 25th of March, though it was later changed to the 21st of March. It was determined that the Vernal Equinox occurred every 365.25 days (365 days + 6 hours) at that time and the calendar year was divided into months, which Caesar named, mostly after pagan deities and Latin words. In order account for the extra six hours per year not included in the 365 day calendar, the wisest scholars and mathematicians of the day came to the logical conclusion that adding one day to the calendar every four years would compensate for the 24 hours difference accumulated over a period of four years. Thus, to this day we add one day to February every 4th year, known as the “Leap Year”. As a point of interest, to determine which years are leap years the following simple mathematical rule applies: The year must be exactly divisible by 4, however it is never exactly divisible by 100, except in the case it is equally divisible by 400. For example: We can determine that 2000 was a leap year because it is divisible by both 4 and 400 equally (2000 ÷ 4 = 500 and 2000 ÷ 400 = 5). We can also see that 2011 is not a leap year because it is not divisible by 4 equally (2011 ÷ 4 = 502.75). We can see that 2012 is a leap year because it is divisible by 4 equally (2012 ÷ 4 = 53).

The calendar seemed to be in sync with the seasons for a time but after 125 years, the Equinox happened a day earlier than expected and it gradually appeared earlier in the month than the day specified on the calendar, revealing that the annual cycle was actually almost eleven minutes shorter than they had originally measured. Today the Vernal Equinox occurs once every 365.2425 days (365 days, 5 hours, 49 minutes, and 12 seconds). After 325 years went by, the Julian calendar’s date for the Equinox was about two and a half days after it had already passed. By 1582 the Equinox was falling on the 11th day of March, ten days earlier than the calendar stated. So that year, under Pope Gregory XIII, ten days on the calendar were “skipped” after the 4th day of October in order to realign the calendar with the Equinox. The following day which would have been the 5th of October, was declared the 15th instead. This temporarily restored March 21st as the date of the Vernal Equinox. Roman Catholic countries immediately adopted the new Gregorian calendar, while Protestant countries were hesitant. Some Christians were hesitant to sway from their belief that Easter was during the Festival of Unleavened Bread, a Jewish feast. Later, the Protestant Christians, too, would conform to the Gregorian calendar (also called the Western calendar, or Christian calendar).

England changed from the Julian calendar, also referred to as the “Old Style” (or O.S. for short) on the 2nd day of September 1752, skipping eleven days following that date so that the “New Style” began the following day, which was called the 14th of September instead of the 3rd. Furthermore, the last three months of 1751, January, February and March were removed from that year and became the first quarter of 1752. Double-dates were used for those three months to differentiate. For any events that happened during those three months, the year was written “1751-52” or “1751/52”.

Therefore, until 1752, the seventh month was actually September, which can be seen by researching the etymology of the word “September”. So when we see “on ye 12th day of ye 7th month 1643” we now know it refers to September 12, 1643. Keep this in mind for dates written in this format prior to 1752.

Unfortunately, over the years, this important fact sometimes causes transcription errors. If you are using this as a resource for clues and are looking for a person said to have been born in a particular month before 1752, but cannot find a match in other records, try looking for one born two months after (or even before) the presumed month, as transcriptions may contain this common error. This is something genealogists should be aware of.


Related Posts

See All


Sign up or log in to save this page to your Site Favorites.

bottom of page