25th March is the Feast of the Annunciation, when the Archangel Gabriel visits the Virgin Mary to inform her that she will bear Jesus Christ who will be born in exactly nine months time, Christmas Day.
Of course it is Lent in the Church of England calendar but Lent has its feasts. Consistency is not the Church’s strong point.
From 1155 to 1752 March 25th was also the start of the New Year. While it moved to January 1st, with a slight tweak- to April 5th- it remains the start of the financial year.
Lady Day is also the start of the contractual year for tenant farmers and a quarter day on which rents etc are due to be paid. It will be celebrated on the Archers on Wednesday evening…
Finally don’t expect to hear much if anything about all this from those who go on and on about British history and traditions even though this is one of the more significant ones.
Kmflett's Blog 
The Spring Equinox, when the sun enters Aries, must have originally been the new year. The date being different, because of the adjustment of leap years would have driven the desire for a regular date.