St. Nicholas, Archbishop of Myra in Asia Minor, from the child like innocence of his own life and his devout care for the young, is looked upon as the patron of children. He died in the middle of the Fourth Century, and seven hundred years later his holy relics were translated to Bari, Italy. Because of the power he exercised over flames, we pray that through his intercession we may be preserved from the flames of hell. He is remembered for the money which he threw in a window that three young girls might have a dowry for their marriage. Because of this gift his name has become associated with giving and children thank Santa Claus (or St. Nicholas) for their presents at Christmastime.
(Source: The New Roman Missal, Rev. F. X. Lasance)