Guglielmo Gonzaga was Duke of Mantua from 1550 to 1587, and of Montferrat from 1574 to 1587. He was the second son of Federico II Gonzaga, Duke of Mantua and Margaret Palaeologina of Montferrat. In 1574, Montferrat was elevated to a Duchy and Guglielmo became its first duke. He was succeeded as Duke of both duchies by his son Vincenzo.

Margherita Barbara Gonzaga, was an Italian noblewoman, Duchess consort of Ferrara, Modena and Reggio between 1579 and 1597 by marriage to Alfonso II d'Este, Duke of Ferrara, Modena and Reggio. She was a significant cultural patron in Ferrara and Modena.