[2]: 252 [3]: 128  He made Giovanni Della Rovere, who was not a priest, prefect of Rome, and arranged for him to marry into the da Montefeltro family, dukes of Urbino.

[4] Guidobaldo da Montefeltro adopted Francesco Maria I della Rovere, his sister's child and nephew of Pope Julius II.

Guidobaldo I, who was heirless, called Francesco Maria at his court, and named him as heir of the Duchy of Urbino in 1504, this through the intercession of Julius II.

Vittoria, last descendant of the della Rovere family (she was the only child of Federico Ubaldo), married Ferdinando II de' Medici, Grand Duke of Tuscany.

They had two children: Cosimo III, Tuscany's longest reigning monarch, and Francesco Maria de' Medici, a prince of the Church.