 In 1496, while fighting for the pope near Bracciano, Guidobaldo was taken prisoner by the Orsini and the Vitelli, being freed the following year.Guidobaldo was forced to flee Urbino in 1502 to escape the armies of Cesare Borgia, but returned after the death of Cesare Borgia's father, Pope Alexander VI, in 1503.He adopted as his heir Francesco Maria della Rovere, his sister's child and nephew of Pope Julius II, thus uniting the seigniory of Senigallia with Urbino.