I’m about to launch myself into the Jacobite Rebellion of 1745 but before that I thought I’d take the opportunity to get my head around the calendar switch that occurred in England in 1752.

Prior to that date in England we followed the Julian Calendar.  The Julian Calendar had a leap year every four years which it turns out is far too many. This system had quite been around since the Romans had been in charge.  The formula for calculating leap years was developed by Julius Caesar (squashed his nose in a lemon squeezer- an unhelpful childhood rhyme) who was trying to reform a system that had somehow got itself approximately three months ahead of what was actually happening to the seasons- unfortunately this meant that in 46 B.C. or B.C.E. the year ran to a whopping 445 days in a bid to get the months synchronised with what the sun was doing.  Unsurprisingly the calendar then took approximately the next forty years for everyone who was using it to be singing from the same ..er..calendar.

Sadly Julius had been advised by a bloke who got his maths ever so slightly wrong to the tune of eleven minutes and 14 seconds per year.  This meant that by the 1500s the dates and the seasons were squiffy once more in that the vernal equinox when the sun shines directly on the equator (the point where day and night are more or less of equal length) was off by ten days which didn’t help if you were trying to work out when to plant your crops.

As a consequence Pope Gregory XIII issued an edict in 1582 declaring that hence forth we should all use a new calendar which made the necessary adjustments and matched the months to the seasons once more. He also decreed that in future a centenary year would not be a leap year unless it was divisible by four hundred. If only it had been that simple.  Sadly the first problem arises for us with the name of the calendar.  It can also be known as the Western Calendar or the Christian Calendar.

This leads us to the second problem that in 1582 not everyone was paying much attention to the edicts of the Pope and some of the Protestant countries actually believed that it was a devious and nasty trick on the part of the papacy. The day after the 4th of October 1582 in Catholic countries such as Spain, Portugal, France and the Vatican was the 15th October 1582 meaning that if historians studying Anglo-Spanish relations between October 1582 and September 1752 want to match dates in the English Archives with those in the Spanish Archives they need to add on ten days increasing to eleven days by the end of the period. Not to do so means that when studying primary materials such as letters it can sometimes appear that replies were sometimes sent from England before the original letter was even penned in Spain or France.

And the third problem was that losing ten days caused riots. Of course by 1752, more time for a leap year every four years had elapsed so the mismatch was even greater than it had been in 1582 so eleven days had to be dropped.  If you’re feeling pedantic and want to calculate the current date on the Julian Calendar you have to knock thirteen days off the Gregorian date now. There was a 1st and 2nd of September 1752 but the next eleven days simply disappeared meaning that you went to bed on the evening of the second and woke up on the 14th of September- which must have been really irritating if you had a birthday during the missing days. Revisionist historians don’t believe that many folk took to the streets demanding their eleven days back but you can imagine the havoc it played with things like pay.

Interestingly the Jacobites seemed to have tried to avoid a date related disaster by dating their cross Channel letters with both dates as do other writers during the calendar mismatch period.

There’s one final difficulty – New Year.  Under the Julian Calendar although the calendar for the year began on the 1st of January just to make life really difficult the actual legal New Year was celebrated on the 25th of March thanks to the Normans. 1752 made it very clear that the start of the year was the start of the year but for reasons beyond my comprehension the financial year  in the United Kingdom still begins on the 6th April (count back eleven!)