Born in
Rome, he was appointed
bishop of Muro Lucano by
Pope Pius IV (Medici) in consistory on 29 November 1560. He held various offices in the
Roman Curia. On 10 July 1561, Flavio Orsini, Bishop of Muro and Auditor of Causes in the Apostolic Camera, transmitted a
motu proprio of
Pope Pius IV granting a feudal investiture to Baldassare Rangoni of Modena. On 3 September 1563, the Bishop of Muro was judge ordinary in the curia, hearing a testamentary dispute from the diocese of Ajaccio. He was transferred to the diocese of
Spoleto on 16 December 1562 by
Pope Pius IV. In his fourth consistory for the creation of cardinals, on 12 March 1565, Pope Pius IV named Flavio Orsini a cardinal-priest, and on 15 May assigned him the
titulus of
San Giovanni a Porta Latina. On 17 November 1565, he chose to be moved to ("opted for")
SS. Marcellino e Pietro, and on 9 July 1578 to
Santa Prisca. On 19 September 1570,
Pope Pius V (Ghislieri) appointed a commission of two cardinals, Giovanni Poliziani and Flavio Orsini, to complete the repairs on the Aqua Vergine and connect various fountains, including the Trevi.
Pope Gregory XIII (Boncompagni) sent Bishop Orsini to France in 1572, to attempt to persuade King
Charles IX of France to join in a crusade against the Turks. He arrived in Paris on October 8, and was still in France in the second half of December. His mission was a failure. On 11 April 1580, he was granted a coadjutor bishop with the right of succession, in the person of his nephew Pietro. Flavio Orsini died in
Pozzuoli, near
Naples, on 16 May 1581. ==References==