Eleanor de' Medici was a Duchess of Mantua by marriage to Vincenzo I Gonzaga. She served as regent of Mantua 1595, 1597 and 1601, when Vincenzo served in the Austrian campaign in Hungary, and in 1602, when he left for Flanders for medical treatment. She was a daughter of Francesco I de' Medici and Joanna of Austria and the sister of Marie de' Medici, Queen of France.

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.