Why is it traditional for women to propose on Valentine's Day in a leap year?

Leap Year was the traditional time that women could propose marriage. In many of today's cultures, it is ok for a woman to propose marriage to a man. Society doesn't look down on such women. However, that hasn't always been the case. When the rules of courtship were stricter, women were only allowed to pop the question on one day every four years. That day was February 29th.

It is believed this tradition was started in 5th century Ireland when St. Bridget complained to St. Patrick about women having to wait for so long for a man to propose. So, according to legend, St. Patrick said the yearning females could propose on this one day in February during the Leap Year.

http://marriage.about.com/cs/holidays/a/leapyear.htm