The changeover from Julian to Gregorian Calendars involved a series of steps:

• December 31, 1750 was followed by January 1, 1750 (under the "Old Style" Julian calendar, December was the 10th month and January the 11th)
• March 24, 1750 was followed by March 25, 1751 (March 25 was the first day of the "Old Style" year)
• December 31, 1751 was followed by January 1, 1752 (the switch from March 25 to January 1 as the first day of the year)

September 2, 1752 was followed by September 14, 1752 (drop of 11 days to conform to the Gregorian calendar)