What comes after 2nd September? 14th September obviously. This Is what exactly happened in September 1752.
To unlock this mystery, you must know what are Leap years and Calendars.
According to Julian calendar (before 1582). It was assumed a year to be 365.25 days long. In order to compensate this fractional day of the year, they added a new day after every four years known as Leap day and the year is called Leap year—thus effectively having 365.25 days every year on an average.
But, the actual length of the solar year (the time taken by the earth to complete one revolution around the sun) is not 365.25 days, but approximately 365.2422 days. This small difference doesn’t cause much of a difference in a short span of 100 years (365.25 – 365.2422 = 0.0078 days per year) i.e. we’re ahead by just 0.78 days per century.
As this malpractice was followed from 46BC to 1582, it caused the calendar to be ahead by nearly 10 days. Catholic’s noticed the religious days were not occurring on the exact same day it used to occur centuries ago. So, Pope Gregory XIII established the Gregorian calendar in 1582.To launch the calendar, ten days were dropped from the calendar. October 4, 1582, was followed by October 15, 1582. Catholic Europe gradually accepted the new calendar.
Needless to say, this way, a time would come when the seasons would not be in sync with the calendars, and so a change was needed as early as possible. The British Empire (The UK and its colonies like India) adopted it as late as 1752. By 1752, an error of about 11 days had occurred. Therefore, eleven days had to be dropped this time, and September 2, 1752 was immediately followed by September 14, 1752. So September 1752 was shorter than other Septembers.
In order to prevent extra days from getting added in the future, the Gregorian calendar recommended that the leap years would still come every 4 years, but we’d need to drop 3 extra days every 400 years. This could be done by eliminating leap days from century years which are not divisible by 400, such as 1700, 1800 and 1900.
Britain and its colonies weren’t the last holdouts for the new form of the calendar. Russia didn’t change over until 1918. Greece refused to switch until 1923. By then the synchronisation had become so bad that the two countries needed to skip 13 days, rather than 11.