Orsini

The Orsini were a great princely house of medieval and Renaissance Rome, claiming descent from Ursus, count of Tivoli in the ninth century. They rose through the Church: Giacinto Bobone Orsini became Pope Celestine III in 1191 and enriched nephews with fiefs, while Matteo Rosso Orsini the Great, as Senator of Rome, defeated imperial troops in 1241 and made himself Rome's effective lord, expelling the Colonna. His many sons founded its several branches.

Pope Nicholas III reigned from 1277 and carried nepotism to new heights; in all the Orsini produced five popes and thirty-four cardinals. Guelph leaders, they feuded for centuries with the Ghibelline Colonna, until a 1511 papal bull ended the violence and marriage reconciled them in 1571.

Clarice Orsini married Lorenzo de' Medici in 1469, linking the family to Florence. The Bracciano line won the ducal title in 1560 under Paolo Giordano I Orsini, a Lepanto veteran of 1571; the family's last pope, Benedict XIII, reigned in 1724—1730.