He was prepared by his father for the life of arms, fighting with him in Tuscany (1478) and then in Otranto against the Turks in 1481. His elder brother Giovanni Antonio died in Pisa in 1479. Upon the death of his father in Otranto, Andrea Matteo, as the elder surviving son, inherited the title of Duke of Atri and Count of S. Flaviano, which made him feudal lord of much of Abruzzo. He also received the maternal fiefdoms with the title of Count of Conversano. In 1482, during the War of Ferrara, he fought for Ferdinand I of Naples on behalf of the king's son-in-law, Ercole I d'Este, Duke of Ferrara against Pope Sixtus IV and his Venetian allies.