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.