1752 and All That: the derivation of the modern calendar – 8pm 19th May 2021

A Talk by Mark Bowman

Why 1752? Well that was the year that Britain changed its calendar system and famously lost eleven days. The title of the talk is a play on ‘1066 and all that’ the hilarious book from the 1930s by Sellars and Yeatman which treats British history very irreverently, long before satire was invented in the 1960s.

So what caused the need for the change of calendar? By 46 BC the calendar used by the Romans was about 3 months ahead of the seasons. The time the earth takes to go round the sun is called a solar year and is approximately 365 and one quarter days, which because we count in whole days means there will be errors accumulating. So Julius Caesar imposed the Egyptian Solar calendar on the Roman Empire. This was based on the above 365.25 days with a leap year every fourth year so that February had 29 days, but two February 23rds and no 29th!

This all sounds more or less familiar and it was called the Julian Calendar. To get things back on track 46 BC had 445 days. The calendar was slight problematical at first but by AD 8 it was working well, except that 365.25 days is an approximation and the Solar Year is nearly 11 minutes and 15 seconds shorter. It doesn’t sound much but it does build up into an error of about 3 days every 400 years.

By the late 16th Century the calender was out by 10 days and Easter was falling on the wrong day, which was almost heretical. (Mark had explained the rules for calculating the date of Easter which were set by the Council of Nicea in 325 AD). Consequently Pope Gregory XIII decreed that in 1582 the date should be advanced by 10 days which made the Vernal Equinox March 20th and Easter fell on the ‘correct’ day.

Other adjustments were incorporated in that 3 out of 4 years ending 00 are not leap years, which keeps the Summer Solstice close to the 21st June. Most Catholic countries happily adopted this Gregorian Calendar, but other Christians (Protestant, Russian Orthodox, Greek Orthodox) did not hold truck with any Popish idea. This was especially true of England, where nearly 50 years before, King Henry VIII had fallen out with the Pope and under Queen Elizabeth the country was vigorously Protestant.

Did it matter? Possibly not but it did cause some strange things. The records show that William Shakespeare died on 23rd April 1616. They also show that Miguel de Cervantes, author of Don Quixote, died on the 22nd April 1616, apparently one day earlier, but as he was in Catholic Spain and Shakespeare was in Protestant England it was actually 11 days earlier. Trade was also a bit difficult. Today we sometimes get a bit crossed up with time zones, like the continent being 1 hour ahead of us. Or having to look at the iPad clock app to see if our son in Australia is likely to be awake if we ring him. So imagine the fun of trying to meet someone if their date is 10 days behind your own!

It could not last and the Gregorian calendar was gradually adopted by various countries from 1582 to 1923, meaning that for 341 years the date depended on what country you were in. Britain and its overseas possessions adopted the new calendar in 1752. 1752 was the shortest year in British history. Whether the people went round shouting ‘Give us back our eleven days’ is debatable, but Mark showed a Hogarth painting with such a banner seen through an open window. It also meant there was a loss of 11 days rent for the Quarter or 11 days occupancy for a quarter’s rent.

Either way a not inconsiderable amount, so the Government moved the tax date to the next year. New Year – King Henry II moved New Year’s Day to 25th March in 1155 and this was the basis for the quarter days – Lady Day (25th March), Midsummer’s Day (24th June), Michaelmas Day (29th September) and Christmas Day, all close to the solstices, or equinoxes. In 1752 with the calendar change New Year’s Day was moved to 1st January, (ordinary people had always regarded 1st January as New Year, even if the state didn’t). The tax year stayed at Lady Day plus 11 days = 5th April. Another day was added in 1800 which is why our tax year begins on 6th April. Mark also said that Guy Fawkes Day should be on the 15th November as the Gunpowder Plot was in 1605, before the calendar change.

What did the rest of the world do? Germany, the Netherlands and Denmark changed in 1700, GB in 1752, Sweden in 1753, Alaska in 1867, China officially in 1912, but in practice it was 1929, the Ottoman empire in 1917, Russia in 1918 and Greece in 1923 (which affected the birthday of the late Prince Philip). The Swedes had actually started the change in 1700 by planning to omit the leap days for 40 years, but due to war they forgot 1704 and 1708, so they were then out with everyone. To sort it out they had a 30th February in 1712 and in 1753, February was only 23 days long.

The Poles had an even more confusing time going Julian – Gregorian – Julian – Gregorian (WWII), depending on who was occupying them at the time. Today the Gregorian Calendar is almost universal, but there are still some others used for local purposes e.g. the Chinese. As the earth’s rotation is not precise and a bit variable due to many factors we do need still need to make occasional very small calendar adjustments called leap seconds.

Thank you Mark for your erudite and humorous explanation of what at times must have been a baffling situation for those involved, let alone to those of us living today.

Richard Brown

P.S. Later that evening I was reading a book which said that the ‘White’ Russians in exile in London before the Second World War still used the Julian calendar, because they loathed the communist Bolsheviks who had moved Russia to the Gregorian calendar in 1918! They must have had fun arranging meetings with other people.

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