From 1419, he fought alongside his father, soon gaining fame for being able to bend metal bars with his bare hands. He later proved himself to be an expert tactician and very skilled field commander. After the death of his father during the War of L'Aquila, he participated in Braccio da Montone's final defeat in that campaign; he fought subsequently for the Neapolitan army and then for Pope Martin V and the Duke of Milan, Filippo Maria Visconti. After some successes, he fell in disgrace and was sent to the castle of Mortara as a prisoner "de facto". He regained his status after leading an expedition against Lucca.