According to their own family legend, the Orsini are descended from the
Julio-Claudian dynasty of
ancient Rome. The Orsini carried on a political feud with the
Colonna family for centuries in Rome, until it was stopped by
Papal Bull in 1511. In 1571, the heads of both families married nieces of
Pope Sixtus V as an act of reconciliation. The Orsini descend from Cajo Orso Orsini who lived c. 600 AD. Five popes are descended from him:
Stephen II,
Paul I,
Celestine III,
Nicholas III and
Benedict XIII. Some members used the surname of Bobone-Orsini. One member by the name Bobone, lived during the early 11th century, father of Pietro, who was in turn father of
Giacinto Bobone (1110–1198), who in 1191 became pope as Celestine III. One of the first great
nepotist popes, he made two of his nephews cardinals and allowed his cousin Giovanni Gaetano (Giangaetano, died 1232) to buy the fiefs of
Vicovaro,
Licenza,
Roccagiovine and
Nettuno, which formed the nucleus of the future territorial power of the family. The Bobone surname was lost with his children, who were called
de domo filiorum Ursi. Two of them, Napoleone and
Matteo Rosso the Great (1178–1246), considerably increased the prestige of the family. The former was the founder of the first southern line, which died out with Camillo Pardo in 1553. He obtained the city of
Manoppello, later a countship, and was
gonfaloniere of the
Papal States. Matteo Rosso, called the Great, was the effective lord of
Rome from 1241, when he defeated the
Imperial troops, until 1243, holding the title of
Senator. Two of his sons, and Napoleone, were also Senators. Matteo ousted the family's traditional rivals, the
Colonna family, from Rome and extended the Orsini territories southwards down to
Avellino and northwards to
Pitigliano. During his life, the family was firmly in the
Guelph faction. He had some ten sons, who divided the fiefs after his deaths: Gentile (died 1246) originated the Pitigliano line and the second southern line, Rinaldo that of
Monterotondo, Napoleone (died 1267) that of
Bracciano, and another Matteo Rosso that of Montegiordano, from the name of the district in Rome housing the family's fortress. The most distinguished of his sons was
Giovanni Gaetano (died 1280): elected pope as
Nicholas III, he named his nephew Bertoldo (d. 1289) as count of
Romagna, and had two nephews and
a brother created cardinals. ==The second southern line==