She was the daughter of
Innico I d'Avalos of the Spanish
d'Avalos family, count of
Monteodorisio, and
Antonella d'Aquino, heiress to the marquisate of
Pescara. Her father had come to Italy with
Alfonso V of Aragon in 1442. She was given in marriage to
Federico del Balzo, Prince of
Altamura and Duke of
Venosa, son of
Pietro del Balzo and brother of the Queen of
Naples,
Isabella. Later that year, she defended Ischia against the French for four consecutive months, with great skill and bravery. Her services were rewarded by the settlement of the civil and military government of the island on the d'Avalos family, which power it retained until 1734, when its military command was transferred to Naples. She established her court at Ischia, which was frequented by many Neapolitan intellectuals of the period. On 13 June 1507, she signed a marriage contract between her nephew
Fernando Francesco d'Ávalos and
Vittoria Colonna. The marriage took place on Ischia in December 1509. Vittoria, shortly after her marriage, spent her time on Ischia with Costanza. In 1523
Charles V granted to Costanza the land which nowadays forms
Pescara. She died in 1541, after Charles V had given her the title of Princess of Francavilla. ==Literary influence==