In 1567 Serbelloni followed the Spanish armies into Belgium under the Duke of Alva during the repression of the Flemish revolt, being appointed twice as governor of Antwerp.
•
With 300 infantrymen at his command, in 1542 Serbelloni distinguished himself against the Ottoman Turks in the defence of Esztergom.
•
Always with his fierce cousin, he commanded the Florentine artillery in the war for Siena in 1554; the nexy year in the summer he first took by assault Porto Ercole fortress after a four-day artillery barrage, then with 700 German Landsknechts he defended Populonia against a Turkish sea-bourne assault, receiving support from the Florentine cavalry.