According to an old Irish legend, St. Bridget struck a deal with St Patrick to allow women to propose to men every 4 years.
In some places, Leap Day has been known as “Bachelors’ Day” for the same reason. A man was expected to pay a penalty, such as a gown or money, if he refused a marriage proposal from a woman on Leap Day. In many European countries, especially in the upper classes of society, tradition dictates that any man who refuses a woman's proposal on February 29 has to buy her 12 pairs of gloves. The intention is that the woman can wear the gloves to hide the embarrassment of not having an engagement ring.