Calendar (New Style) Act 1750
The Calendar (New Style) Act 1750 (also known as Chesterfield's Act is an Act of the Parliament of Great Britain (statute chapter book number 24 Geo II c. 23). It reformed the calendar of England so that a new year began on 1 January rather than 25 March (Lady Day) and would run according to the Gregorian calendar as used in Scotland and the rest of Europe.
Thus, in England the year 1751 commenced on 25 March and ended on 31 December, with 1752 beginning on 1 January. An additional correction to the calendar made by the act to acocunt for the fact the Julian calendar was twelve days behind the Gregorian calendar meant that the 2 September 1752 was followed by 14 September 1752.