08 Oct What happened between 5 and 14 October 1582?
Posted at 20:22h in Hispanic culture by strasbourg 0 Comments
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Nothing, they didn’t exist… On 4 October 1582, the inhabitants of Italy, France, Spain and Portugal fell asleep, only to wake up ten days later on exactly 15 October. There was no illness or strange paranormal phenomena involved; it was simply an administrative procedure: a calendar change.
At the time, the Western world used the Julian calendar, introduced by the Roman ruler Julius Caesar in 46 BC. The Julian calendar – introduced to Europe by Julius Caesar, who was inspired by the Egyptian calendar – was fairly accurate, but it had one minor flaw: it set the length of the year at 365 days and 6 hours, whereas in reality it was 365 days, 5 hours, 48 minutes and 45 seconds, which meant that each year the official date was 11 minutes and 15 seconds off the astronomical date. This difference is minimal, but in over 1600 years of existence, the Julian calendar has already accumulated a delay of almost 10 days.
The problem with this calendar was that it was longer than it should have been: the Earth’s translation around the Sun lasts 365 days, five hours, 48 minutes and 45.25 seconds. The Julian year was about 11 minutes and 14 seconds longer, according to Encyclopaedia Britannica. In fact, the error is not surprising: it had been known since the 4th century that the Julian calendar was not entirely accurate and, in the 13th century, the astronomers of King Alfonso the Wise of Castile had recorded, in the “Alfonsine tables”, an almost exact calculation of the time difference, which they had set at 10 minutes and 44 seconds per year.
Despite this, no action was taken. Apart from the fact that the discrepancy was minimal, the reason was that the most important calendar in Christian Europe was not the civil calendar, but the liturgical calendar, and for centuries it had no impact on the dates. The problem only began to arise when the accumulated error affected the date of Easter, which had been set for the Sunday following the first full moon in spring.
It was for this reason that Pope Gregory XIII decided to set up a “calendar commission” to make the necessary corrections, based on the astronomical studies available. This commission included scholars such as Christophorus Clavius, an astronomer to whom Galileo himself turned, and Luigi Lilio, the main author of a calendar proposal that was taken as a model. Lilio died in 1576 without seeing the birth of the new calendar, which was finally approved in September 1580, although its implementation was delayed until October 1582. So Thursday (Julian) 4 October 1582 was replaced by Friday (Gregorian). And although few people know it, the astronomers of Salamanca contributed to its reform, as described in Ana María Carabias Torres’ book, Salamanca y la medida del tiempo, “which shows that those who really laid the foundations of the current Gregorian calendar were professors at the Studium de Salamanca and not the Italian Luigi Lilio, as has been believed until now”. The professor explains why October was chosen to implement the change. “We looked for a time when there were few special religious celebrations. In October, the ecclesiastical calendar had fewer festivals and it was easier to do away with them”, explains the blog. “This reform of 1582 undoubtedly marked the beginning of globalisation, by imposing one date and one time on the world”, and this process, which “began in Salamanca”, is still in force today”, adds the author of the text.
These two university reports laid the foundations for the current calendar. Over the decades, the rest of the world adapted to the new almanac. First the Catholics, like France, then the others. England waited until 1752 and Russia until 1918.
The switch from one calendar to the other has given rise to some curious anecdotes. Perhaps the most curious is that, although Cervantes and Shakespeare are jointly honoured on Book World Day, neither of them died on that day: the Castilian died on 22 April 1616 but was buried the following day, while in Anglican England the Julian calendar was still in force and, as a result, when it was 23 April in Spain, it was already 3 May.
Sources:
– National Geographic, “La implantación del calendario gregoriano, el año que desaparecieron diez días en una noche”.
– El Norte de Castilla, “Un ‘viaje en el tiempo’ gestado en Salamanca”.
– Diarium Usal, “Eureka El calendario Gregoriano y la Escuela Salmantina”.
– BBC News Mundo, “1582, el año en el que el mundo occidental pasó del 4 al 15 de octubre (saltándose los días intermedios)”.
