He took service with Cesare, spurred by the hope of ultimately finding a way to avenge himself upon the Florentines, and in Cesare's train he now advanced upon Imola and Forli.
The warlike Countess Caterina Sforza-Riario had earlier been granted by her children full administration of their patrimony during their minority.

To the defence of this she now addressed herself with all the resolution of her stern nature.

Her life had been unfortunate, and of horrors she had touched a surfeit.

Her father, Galeazzo Sforza, was murdered in Milan Cathedral by a little band of patriots; her brother Giangaleazzo had died, of want or poison, in the Castle of Pavia, the victim of her ambitious uncle, Lodovico; her husband, Girolamo Riario, she had seen butchered and flung naked from a window of the very castle which she now defended; Giacomo Feo, whom she had secretly married in second nuptials, was done to death in Forli, under her very eyes, by a party of insurrectionaries.

Him she had terribly avenged.