Background
He was the illegitimate son of Alfonso I d'Este, Duke of Ferrara by his lover Laura Dianti. In 1523 his father gave him Montecchio and turned it into a feudal inheritance for cadet members of his family – in 1569 it was promoted to a marquessate by Maximilian II, Holy Roman Emperor.
Career
Alfonso d'Este (1560–1578), married Marfisa d'Este;
Cesare d'Este (1562–1628), married Virginia de' Medici. The legitimacy of the succession was recognized by the Emperor Rudolph II but not by Pope Clement VIII: thus, as Ferrara was nominally a Papal fief, the city was returned to the Papal States, despite the attempts of the young duke, who sought help from the Major Powers to no avail. The Este family thus lost the duchy of Ferrara.
Eleonora d'Este (1561–1637), married Carlo Gesualdo di Venosa;
Ippolita d'Este (1565–1602), married Federico Pico, duke of Mirandola. He also had one illegitimate child:
Alessandro d'Este (1568–1624), cardinal.