25/03/2026
Calendars and Old and New Style dating
A number of major and somewhat complicated calendar changes took place in 1752.
Before that time, the Julian calendar was used in Great Britain. Inaccuracies in the design of this calendar resulted in a calendar year that was slightly longer than the natural solar year. Over the centuries this tiny discrepancy accumulated, and by the 1750s the calendar was 11 days out of alignment with the solar year. Change was needed and the Calendar (New Style) Act of 1750 was passed. As a result, the more accurate Gregorian calendar was introduced in 1752. The timing of leap years was restructured, and the problematic discrepancy was removed by ‘skipping’ 11 days that September and going immediately from the 2nd to 14th September. The 3rd to 13th September 1752 never technically took place!
A second major change concerned the start of the legal year. For many centuries, the legal year started on Lady Day (25th March) and ended on 24th March. When the calendars were changed in 1752, the beginning of the year in England was officially moved to 1st January. Scotland had already made this change in 1600.
These changes cause a number of issues when it comes to interpreting dates on documents...
• Pre-1752 official records are typically dated according to the old legal year, which deviates from our modern notion of when a year starts and ends. For example, 3rd December 1710 comes before 3rd January 1710 under the old system – remember, 1711 didn’t start until 25th March! The system can be seen most clearly in records listing events chronologically, including some parish registers (pictured)
• The Gregorian calendar had been introduced in other European countries as early as 1582, and the shift in the start of the year sometimes even earlier. This meant that for over a century, a document written in France might bear a quite different date to one written at exactly the same time in England
• Although the ‘legal’ year started on 25th March, the concept of the year commencing on 1st January was also understood and in common use by the ordinary people of England before 1752. Therefore, creators of English documents would sometimes record a date with the day, month and both versions of the year. This was known as double or dual dating and would only need to be applied to dates between 1st January and 24th March. An example can be seen on the pictured marriage bond, dated 22 March 1745/6
Our modern archival policy is to record years according to our current calendar. When cataloguing, archivists will typically 'roll' dates between 1st January and 24th March, on official documents written before 1753, into the next year. A document dated February 1702 may therefore be in our catalogues with the year as 1703 – although it was still 1702 for the writer, by our modern understanding we were already a couple of months into 1703. In handwritten archive catalogues in particular, ‘double dating’ by recording both ‘old style’ and ‘new style’ dates can often be seen. Alternatively, ‘O.S’. or ‘N.S’. is sometimes used to indicate the dating convention.
The legacy of the old calendar can still be seen reflected in the fiscal or tax year, which used to end on the old ‘new year’s day’, Lady Day. When the official calendar changed, it was decided that taxation should continue to be based on the old year. And when those 11 days were skipped in September 1752, this shifted the end of the tax year from 25 March to the 5th of April.