In 1393 Antonio di Acquaviva, who was the first to hold, by concession of Charles III of Naples, the titles of Count of San Flaviano and Montorio.

Giulio Antonio I, son of Giosia and seventh Duke of Atri, commanded the fleet that supported the Neapolitan army of King Ferrante of Aragon, which had joined the coalition formed by Pope Sixtus IV against the Republic of Florence in 1478.

He was succeeded by his elder son, writer Andrea Matteo III (1456–1528), eighth Duca d'Atri.

Upon the defeat of the conspirators, Duke Andrea was spared due to the intervention of his father-in-law, Antonio Piccolomini, who happened to be the King's son-in-law.

Unlike his brother, the 8th Duke of Atri, who supported the French, Belisario fought against Charles VIII of France, and was rewarded by King Ferdinand II of Naples with the fief of Nardò and the title Count.

He was later made Duke of Nardò by Charles V.[4] Belisario was hence able to not only preserve his own patrimony, but to procure the restitution of his brother's.