Cosimo I de' Medici, Grand Duke of Tuscany
On 3 September 1558 he married Isabella de' Medici, daughter of Cosimo I de' Medici, Grand Duke of Tuscany, at Poggio a Caiano. Paolo Giordano lived mostly in Rome and his castle at Bracciano, rather than with his wife, who stayed mostly at Florence. In 1571 he took part in the battle of Lepanto. A year later, in October 1572, he served as a general of the Spanish infantry, in a campaign that tried to reclaim the garrison of Navarino in the Peloponnese.