As a result of Pope Gregory XIII's decree, there were changes from the Julian to Gregorian calendar in 1582:
Change the first day of the year from March 25th to January 1st.
To realign the Vernal Equinox with March 21st, drop 10 days from October 1582
Reduce the number of possible leap years in the Julian calendar, a leap year occurred every four years.
The British government adopted the Gregorian calendar from September
The change was implemented in all of the British colonies in North America by William Dollarhide.
One of the last European countries to adopt the calendar change was British.
After Pope Gregory XIII decreed, the new calendar would be followed thereafter.
The change of the new calendar took place in all of the Catholic countries of Europe in 1582.
But the Protestant countries of Europe did not go along with Pope Gregory's decree in 1582
When the British finally adopted the new calendar in 1752, there was the correction needed to bring the Vernal Equinox back into alignment was 11 days.
Britain's parliament decided to drop 11 days from the month of September 1752, eliminating days 3 to 13. From Wednesday 2nd to Thursday 14th, no dates took place.
Britain's parliament declared that the first day of 1753 would be January 1st. Hence, the English year of 1752 was of only 280 days long.