She thus found herself at once unarmed, and not having any other source, sought the assistance of Alfonzo, king of Aragon and Sicily, adopted him as her son, and engaged Braccio of Montone as her captain, who was of equal reputation in arms with Sforza, and inimical to the pope, on account of his having taken possession of Perugia and some other places belonging to the church.

After this, peace was made between the queen and the pontiff; but King Alfonzo, expecting she would treat him as she had her husband, endeavored secretly to make himself master of the strongholds; but, possessing acute observation, she was beforehand with him, and fortified herself in the castle of Naples.

Suspicions increasing between them, they had recourse to arms, and the queen, with the assistance of Sforza, who again resumed her service, drove Alfonzo out of Naples, deprived him of his succession, and adopted Louis of Anjou in his stead.
Hence arose new contests between Braccio, who took the part of Alfonzo, and Sforza, who defended the cause of the queen.

In the course of the war, Sforza was drowned in endeavoring to pass the river Pescara; the queen was thus again unarmed, and would have been driven out of the kingdom, but for the assistance of Filippo Visconti, the duke of Milan, who compelled Alfonzo to return to Aragon.

Braccio, undaunted at the departure of Alfonzo, continued the enterprise against the queen, and besieged L'Aquilla; but the pope, thinking the greatness of Braccio injurious to the church, received into his pay Francesco, the son of Sforza, who went in pursuit of Braccio to L'Aquilla, where he routed and slew him.