He first rose into notice at the battle of Monza in 1412, when Filippo Maria Visconti observed his capacity and bravery, and afterwards advanced him to the captaincy of a troop.

Having helped to reduce the Visconti duchy to order, Carmagnuola found himself disgraced and suspected without good reason by the Duke of Milan; and in 1426 he took the pay of the Venetians against his old master.

During the next year he showed the eminence of his abilities as a general; for he defeated the combined forces of Piccinino, Sforza, and other captains of the Visconti, and took them prisoners at Macalo.

Carmagnuola neither imprisoned nor murdered his foes.[1] He gave them their liberty, and four years later had to sustain a defeat from Sforza at Soncino.

Other reverses of fortune followed, which brought upon him the suspicion of bad faith or incapacity.