Giovanni Gaetano Orsini

Giovanni Gaetano Orsini (c. 1285 – 27 August 1335), Cardinal of the Holy Roman Church from 17 December 1316 until his death, was a Roman nobleman, a nephew of Pope Nicholas III and a grandson of Matteo Rosso Orsini.

He was sometimes recorded under the names Gian Gaetano Orsini and Giangaetano Orsini. He was thus a member of the Monterotondo branch of the Orsini family. Born about 1285, he was given exactly the same name as his father's brother, Giovanni Gaetano Orsini, better known as Pope Nicholas III, who had died in 1280.

He was enrolled at the University of Padua from 1308 to 1310 and studied letters, including rhetoric. He seems not to have made a study of law formally, but he had a wide knowledge of it, while he had very little of theology. He was already a canon of Reims Cathedral before 1308.

The interests of the Pope were more scholarly than political, and he entrusted many practical decisions to Orsini. At the end of 1327, an embassy from Rome to Avignon offered the Pope a stark ultimatum: if he did not immediately return to the city, Rome would submit to his opponent Ludwig of Bavaria. The Pope declined to be commanded, and Orsini attempted to enter Rome but was turned away, retaliating by placing an interdict on the city. In January 1328 Ludwig was crowned Holy Roman Emperor in Rome and installed as Antipope Nicholas V. However, Ludwig was almost entirely dependent in Rome on Sciarra Colonna and lacked the support of Stefano Colonna the Younger. In the summer of 1328, his remaining support melted away when Robert, King of Naples, sent a fleet to blockade the port of Ostia, while Orsini massed forces outside the city. Ludwig and his antipope fled the city on 4 August, and Orsini entered it triumphantly on Sunday, 8 August. Ten days later an Angevin army led by William, Count of Eboli, marched into Rome in the name of Robert of Naples. Late in 1328, Orsini began a campaign against Corneto and Viterbo, which were harbouring the antipope. Both cities submitted to papal authority in 1329. The same year, the antipope also surrendered himself to the Pope, while Ludwig remained as a powerful enemy of the Pope in his Empire to the north.

In August 1334, the Pope cancelled Orsini's legation. Orsini returned to Avignon, where he remained until his death a year later. He died on 27 August 1335 at Avignon and was entombed there in the church of the Franciscans.