If you’ve looked at legal documents or official government documents from previous centuries you probably noticed the use of regnal years instead of the usual calendar system.

Regnal years work like this: the month and day of the month are just as we use them, so this post is publishing on 1st August. However, instead of the year 2022, we write the year of the monarch’s reign. So today is 1st August 71 Elizabeth 2. In other words, 1st August in the 71st year of the Reign of Elizabeth II. Elizabeth’s reign commenced on 6th February 1952, so that’s the date her regnal year changes, hence 5th February of this year was 5th February 70 Elizabeth 2, and the following day was 6th February 71 Elizabeth 2.

Fortunately we no longer use this system, but believe it or not, its use in parliamentary documents was not brought to an end until 1962! (Acts of Parliament Numbering and Citation Act 1962)

Here’s a seventeenth century example from my own research:

Obviously there is a problem with all this: we have to know the date of accession of the named monarch. To help with this here’s a handy Regnal Calendar Table. Scroll down a little to the second section.

Working with my example above, we can see that William and Mary reigned together for six years. They acceded to the throne on 13th February 1689, so this is the date on which each new regnal year will start. The last day of their reign was 27th December 1694, and the reign of the following monarch, William III (this is the same William, following Mary’s death) commences the following day: 28th December 1694. This will be the date each new year of his reign commences.

If you get your genealogy research back as far as the very end of the 12th century you’re in for a special treat: King John’s regnal year was based on the date of his coronation rather than his accession. However, his coronation took place on Ascension Day – a moveable feast. Go back to the Regnal Calendar link and this time scroll down to the notes at the bottom. There, you’ll find a list of the commencement dates of the eighteen years of John’s reign. You’ll see, for example, that Year 3 commenced on 3 May 1201, while Year 4 started 23 May 1202. In other words, the regnal year John 3 had two x 3rd May, two x 4th May, and so on, right up until two x 22nd May. (Horrors!)

In my own example, the calculation is very easy: the document was written on the first day of May in the first year of William and Mary’s reign, so 1st May 1689. However, even setting aside King John, it isn’t always that easy; and since a long reign can involve a bit of mental gymnastics, you can find Regnal Years Calculators like this one online. If you input ‘William and Mary’, the ‘1st of May’, and year of reign ‘1’, you’ll be told that these monarchs reigned from 13 February 1689 to 27 December 1694, and the year of your query is 1689 AD. [Note: the Wikipedia entry gives an explanatory note about the transition from William & Mary to just William. Some sources state that William continued using the same regnal years as previously; others say not.]

We now have another complicating factor to throw into the mix, and one with which I know most of you will be very familiar. Prior to 1751-1752, the Christian year began on 25th March, this being the Feast of the Annunciation. Until then, this was the changeover date for the new year in all parish records. So 24th March 1688 was followed by 25th March 1689. For clarification, historians and genealogists use ‘double-dating’ for the days prior to 25th March in each year, and luckily the Regnal Calculator takes this into account too. Look again at William and Mary on the calculator, and this time input ‘1st of January’ and year of reign ‘1’. This time you’ll be told the year of your enquiry is 1689/90 AD. To clarify: the 1st of January William and Mary 1 comes *after* the 1st of May of that same regnal year. You can try this for any monarch prior to 1751 (the changeover came in the 25th year of the reign of George II): input a date before 25th March and another one in the same year after that date, and you’ll see the year change.

To conclude, here’s another example…

What we might think of as 1st January 1727 would be 1st January 1726 in the parish registers and 1st January 13 George 1 in legal and parliamentary documentation. We would record it as 1st January 1726/27.

Six months later, 1st July 1727 would be recorded just so in the parish registers but in legal and parliamentary documents would be 1 George 2.

We genealogists have to keep our wits about us, don’t we!