by Angelica Raene

Created on: July 08, 2009   Last Updated: July 10, 2009

Imagine falling asleep one night then waking up 12 days later the next morning. This was exactly what happened to people in the British Empire ruled under George II in 1752. They fell asleep on Wednesday, September 2 and woke up on Thursday, September 14. However, this was not a reenactment of the scene in the story "Sleeping Beauty" where the kingdom falls into a deep sleep. It was not the result of a mysterious phenomenon! The Kingdom of Great Britain, the rest of the British Empire, and the eastern part of what is now the United States adopted the Gregorian calendar on September 2, 1752. It was necessary to correct the eleven day difference between the Julian calendar and the Gregorian calendar.

The Julian calendar added a leap year (with an extra day every four years). There were no exceptions to this rule. The length of the Julian year was exactly 362.25 days. The time it takes for the Earth to go around the Sun once is closer to 365.242199 days. The result is a difference of just over 11 minutes and 14 seconds each year. Over a period of 128 years even the Julian Calendar was in error by one day with respect to the seasons.

The use of the Gregorian calendar was first suggested by the Neapolitan doctor, Aloysius Lilius, and was made official by Pope Gregory XIII, for whom it was named, on February 24, 1582. Pope Gregory XIII was concerned about the errors occurring in the Julian Calendar. To guard against further accumulation of error, in the new Gregorian Calendar, Pope Gregory XIII decreed that century years that are not divisible by 400 were not to be considered leap years. Thus, 1600 was a leap year but 1700 was not. As a result, under the Gregorian calendar it would take 3322 years to accumulate to 1 day (compared to the Julian calendar's 128 years).

It is interesting that not all countries adopted the Gregorian calendar immediately. It was adopted by mainly Catholic countries, but Protestant countries were not quick to adopt it. As a result, the date could change by 10 days simply by crossing certain country borders! To this day many Orthodox churches still follow the Julian calendar, which now lags 13 days behind the Gregorian.

Another interesting result of the British adoption of the Gregorian calendar in 1752 is the date of George Washington's birthday. He was born on February 11, 1731, according to the calendar in use on his birthday, but today his birthday is celebrated on February 22, 1731 (actually, that has now changed with the advent of Presidents Day).

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