Changed the Calendar

You may have come across some unusual change of dates if you go back far enough. Such a change that you can be impacted as you do your research. This is the calendar change of 1752. The change can certainly cause some confusion even if it did help make corrections in dates and time.

In September 1752, eleven whole days were cut from the calendar, eradicating them forever. It is as if those days simply never existed – no births, no marriages, no deaths. At this same time, the New Year date was moved from March 25 to January 1st. A full year would now be January 1 to December 31st  rather than March 25th to March 24th. To show the confusion you could have an ancestor married on April 26, 1710 and died on February 2, 1710.

What was changed was the Julian calendar, done during the time of Julius Caesar in 46 BC. This calendar was accepted all over the rule of the Roman Empire and even later after the Fall of Rome. Over the decades and the spread of Christianity people realized that the Julian calendar dates became out of sync with celestial and religious events.

By 1582 Pope Gregory XIII refined the Julian calendar mathematically to fix this mistake and created a new system which we now know as the Gregorian calendar. It started was October 4, 1582.

Between this time and 1752 BOTH calendars, old and new style, were used in Europe in different locations – which would make research in the 20th century even harder.

The original Julian calendar had a New Year of March 25th and the new Gregorian calendar had a New Year of January 1st, a date existing between those times would often be written with both years.

People keeping records of births, marriages and date had to use a double date. If born February 12, 1692, it would be written February 12, 1692/1693 – covering both dates.

It was Great Britain in 1751 who passed laws to solely use the newer Gregorian calendar and that included any of the British colonies – such as the American Colonies. Of course, being different, some regions in British colonial America started using the new Gregorian calendar before the official starting date — more confusion. Some other separate European nations also started solely on the Gregorian calendar before the starting date, which can make it even more confusing for researchers today.

Yet it was found that between 1580s and 1750s that several days (11 days) had been added to the calendar due to leap year. So when the formal switch was made, a change of dropping eleven days had to be done. Now the dates of September 3 to September 13 simply never existed for those in the Julian calendar world. To understand the leap years, the Gregorian calendar has the same months and month lengths as the Julian calendar, but, in the newer Gregorian calendar, year numbers evenly divisible by 100 are not leap years, except that those evenly divisible by 400 remain leap years. So leap year is now every four years.

To help figure old and new dates use this calendar date converter supplied by

Photos: Gregorian calendar, 1752 September; and 1582 calendar.

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