We used to have a link to an excellent web site which gave details of all the changes that have happened
to the calendar in Britain from early Roman times up to date. Unfortunately this site is no longer available,
so we have compiled our own page here.

The Julian Calendar

The Julian Calendar was used in Britain from the time of the Roman invasion until 1752.   The Roman year exceeded the length of the mean solar year by just over 11 minutes, which meant that, after several centuries it became difficult to work out the date of Easter. By the 16th century it was rapidly moving into early summer!

The rule for leap years in the Julian Calendar was that if the year was divisible by 4 then an extra day was added before February 25th.

The new year was generally taken in Britain to begin on Lady Day (March 25th), which led to the use of dual dates during the period leading up to the adoption of the new calendar.  For example, you will find the date in Giles Moore and in parish records shown as for example 20th February ¹⁶⁵¹/₅₂.

The Gregorian Calendar

In 1582, Pope Gregory issued a papal edict establishing calendar reform. As might be expected, the middle ages being rather like today, we didn't like Europe telling us what to do so this took some time to be adopted by Britain. We changed our calendar nearly two centuries later in 1752!

The new rules were as follows:

The rule for leap years was changed - the new rule states that a year is a leap year if:

• it is divisible by 4 and
• if it is divisible by 100, then it is also divisible by 400.

So 1600 and 2000 are leap years, but 1700, 1800, 1900 and 2100 are not.

The first day of the year is January 1st.

If an extra day were needed then it would be the day following February 28th.

To bring the Spring Equinox back to 21st March, eleven days had to be added to the calendar to compensate for the drift caused by the inaccuracy of the Julian Calendar.   This was achieved by "losing" the 4th to the 13th of September 1752, so that 3rd September 1752 was immediately followed by 14th September 1752. This caused an outcry from the public, who thought that eleven days had been "stolen" from their lives and demanded them back!

It also accounts for the strange date for the beginning of the financial year.  When the 11 days were removed from the calendar in September, what would have been 25th March became 6th April.  The financial year thus remained the same despite the changes to the normal calendar.