As the couple had no surviving male issue, Duke Francis' brother Ferdinand succeeded him in the Duchy of Mantua, whereas in the Duchy of Montferrat he was succeeded by his three-year-old daughter Maria, because it had been historically inherited by females, as it was a margraviate of Aleramici origin following a different rule of succession.

Indeed, it had been brought to the Mantuan princely dynasty (the House of Gonzaga) by the marriage of Margherita Paleologa, Margravine of Montferrat, in 1531.

They had to wage war, but in the end their line prevailed and they commanded universal recognition as Dukes of Mantua and Montferrat.

Upon the death in 1633 of her maternal aunt, Archduchess Isabella Clara Eugenia, ruler of the Low Countries,[2] her brother Victor Amadeus became heir to the rights of their maternal grandmother Elisabeth of Valois, eldest daughter and heiress of Henry II of France and Catherine of Medici.

In an assembly known as the Cortes de Tomar, the Spanish monarch maintained the Portuguese kingdom in an Iberian dynastic union, separate from Spain, and promised some local rule through a viceroy, who was meant to have local ties either to Portugal or the Spanish royal family.