You’ve got to feel sorry for St. Oswald, late Archbishop of York, the poor chap is the only saint whose festival only occurs in a Leap Year (actually the church tends to move his festival forward a day in standard years so he doesn’t miss out).
Compared to some other saints his life was not particularly exciting and his main interest seems to have been discouraging the clergy from marrying. In 991 he died of illness rather than undergoing some spectacular martyrdom.
There is an old tradition that women can ask their partners to marry them at this time and the man is not supposed to refuse. Queen Margret of Scotland seems to have liked this idea so much that, according to legend, she made a law in 1288 that any man who refused such an offer had to give the lady in question a kiss and a new silk gown. If the gentlemen in question had been Greek he might still have refused as the Greeks believe Leap Year marriages are doomed to end in divorce. In England, Leap Year babies were thought to be sickly and difficult to rear, although at least they get to have a choice of two possible birthdays - the 28th February or the 1st March.