Giovanni Antonio Orsini

Giovanni Antonio Del Balzo Orsini
Grand Constable of the Kingdom of Naples
Peter Paul Rubens's copy of The Battle of Anghiari by Leonardo da Vinci. Allegedly the 2 knights at right are Ludovico Trevisan and Giovanni Orsini.
Detail Titles and styles Prince of Taranto, Duke of Bari, Count of Lecce, Acerra, Soleto and Conversano, as well as Count of Matera (1433–63) and of Ugento (1453–63)
Born	1386 or 1393
Died	15 November 1463
Noble family	Orsini
Spouse(s)	Anna Colonna
Father	Raimondo Del Balzo Orsini, Prince of Taranto
Mother	Mary of Enghien, an heiress of the Brienne main branch

Giovanni Antonio (Giannantonio) Del Balzo Orsini (1386 or 1393 – 15 November 1463) was a southern Italian nobleman and military leader; he was Prince of Taranto, Duke of Bari, Count of Lecce, Acerra, Soleto and Conversano, as well as Count of Matera (1433–63) and of Ugento (1453–63).

He was the son of Raimondo Del Balzo Orsini, Prince of Taranto, and Mary of Enghien, an heiress of the Brienne main branch. When his father died, he was one year old, and his mother married with king Ladislaus of Naples, who acquired all the family's possessions (1407).

In 1417 Giovanni Antonio married Pope Martin V's niece Anna Colonna, daughter of the Prince of Amalfi. After James II' renounce, he received the Principality of Taranto from queen Joanna II of Naples on 4 May 1421. This act made him the most powerful baronal lord of the Kingdom of Naples, with lands including 7 archbishoprics, 30 bishoprics, 300 castles an extending from Salerno to Taranto.

Giovanni Antonio was also an influent member of the Neapolitan court, and remained engulfed in the struggle between Joanna and Alfonso V of Aragon, whom he supported in the civil war against John II of Anjou. When Alfonso became king of Naples, Giovanni Antonio further increased his power with the titles of Grand Constable and of Duke of Bari.