Complex sentence: Francesco Gonzaga (12 June 1538--6 January 1566) was the Duke of Ariano, brother of the Cardinal Gianvincenzo Gonzaga, nephew of Cardinal Ercole Gonzaga and of Francesco III Gonzaga, the Duke of Mantua.
Split into simpler sentences: Francesco Gonzaga (6 December 1538--6 January 1566) was an Italian nobleman, who was Duke of Ariano. He was brother of the Cardinal Gianvincenzo Gonzaga, nephew of Cardinal Ercole Gonzaga and of Francesco III Gonzaga, Duke of Mantua.