An ancient and illustrious Italian family from which, by an offshoot founded by Welf IV., who became Duke of Bavaria in the 11th century, the Guelph Houses of Brunswick and Hanover, also called the Este-Guelphs, trace their descent. Of the Italian branch the most noted descendant was Alphonso I., a distinguished soldier and statesman and patron of art, whose second wife was the famous Lucrezia Borgia. His son, Alphonso II., is remembered for his cruel treatment of Tasso, placing him in prison for seven years as a madman who dared to make love to one of the princesses.