Before 1752, Great Britain (with the exception of Scotland) and the British Empire used the Julian calendar. While 01 January was sometimes celebrated as a new year as well, legally the new calendar year began on 25 March. It was also known as Lady Day or the Feast of the Annunciation, which commemorates the visit of the archangel Gabriel to the Virgin Mary.
Lady Day was one of the four quarterly dates of the English calendar, and is the closest of these to the vernal equinox, when the amount of daylight and nighttime is almost exactly the same across the country. This made it a logical starting point for the agricultural season, and therefore the legal year.
The Calendar Act of 1750
The Calendar (New Style) Act of 1750 meant that Britain and
its Empire had to adopt the Gregorian calendar, which would bring them in line
with the rest of Europe. This made 1751 the shortest year on record, with just
282 days. As the last year with a New Year in March, it ran from 25 March 1751 until
31 December 1751. 1752 started on 01 January, and was the first year to finish on 31 December.
Genealogy
It’s important that genealogists are aware of this difference
in dating. For example, it’s entirely plausible to see somebody marry in April 1706, and die
in February 1706, as February 1706 is ten months after April 1706. Likewise,
due to the short year in 1751, there was no January of February of 1751 at all.
The correct way to write a date between 01 January and 24
March prior to 1752 is by stating the Old Style (OS) and then the New Style
(NS). For example, Charles I was executed on 30 January 1648/49. In England where his execution took place, 1649
didn’t start until 25 March, so it was referred to as 1648. However, in
Scotland and many parts of Europe, they made the switch earlier, meaning that
they would have given the date of his death as 30 January 1649.
Tax Year
This switch from one calendar to another is also why the tax
year begins on 6 April. Prior to 1752, the tax year began on 25 March also.
However, when switching from Julian to Gregorian (the calendar we use to this
day), a jump was needed to align England with the rest of Europe; so after
Wednesday 2nd September 1752, came Thursday 14th September 1752.
The government didn’t want to miss out on these eleven days
of tax revenue, so the start of the tax year was then brought forward by eleven
days, making the tax year start on 05 April. Another day was added in 1800 to
account for a missed leap year, making the start of the tax year 06 April,
where it has remained ever since.