Topic summary
New style

Extracted from the Wikipedia article Old Style and New Style dates.
Britain and its colonies or possessions
In the Kingdom of Great Britain and its possessions, the Calendar (New Style) Act 1750 (24 Geo. 2. c. 23) introduced two concurrent changes to the calendar. The first, which applied to England, Wales, Ireland and the British colonies, changed the start of the year from 25 March to 1 January, with effect from "the day after 31 December 1751". (Scotland had already made this aspect of the changes, with effect from 1 January 1600.) The second (in effect) adopted the Gregorian calendar in place of the Julian calendar. Thus "New Style" can refer to the start-of-year adjustment, to the adoption of the Gregorian calendar, or to the combination of the two. It was through their use in the 1750 act that the terms and notations "Old Style" and "New Style" came into common usage.