The postings on this site are: The Royal Prerogative; Date of Magna Carta; What Is Magna Carta; Charter 2015, The Clauses of Magna Carta; Knights of Gaia.
The day the English barons and King John signed the Magna Carta is often regarded as the first tentative step from absolute monarchy to government by the people. Nothing is ever this straightforward but in a recent poll by The Times newspaper a quarter of the five thousand people polled voted the Magna Carta as the most important milestone in English Constitutional history. The event took place at Runnymede an island in the River Thames on 15th June 1215.
But in the 18th century the Vatican started harmonising everyone’s calendar. There were sound reasons for this because the sun and moon were getting out of alignment. In England the loss of eleven days this entailed happened in September 1752 shifting Christmas to just 355 days after Christmas 1751. The complications rippled on for centuries.
In the Gregorian calendar the years 1800 and 1900 were no longer leap years but in the Julian calendar they were. This resulted in the difference between the two calendars increasing to 12 days after February 1800 and then to 13 days a century later. 2000 was a leap year in both calendars. So Old Christmas Eve that was on the 4th January in 1753 is now on 6th January every year and coincides with Twelfth Night.
Be that as it may one way or another in England eleven days have been lost since Magna Carta was signed in 1215. So to avoid confusion about the 800th anniversary in 2015 it makes sense to associate Magna Carta II with the Summer Solstice rather than with a specific date like the 15th or the 26th.