BOSO (d. 1181?), third English cardinal, is described by Cardella as Boso Breakspear, an Englishman by birth, the nephew of Pope Adrian IV (Nicholas Breakspear), and a monk of the order of St. Benedict. He was a member of the monastery of St. Albans, but went to Rome to follow the fortunes of his uncle. In 1165 (Ciaccone) he was created cardinal-deacon by the title of St. Como and St. Damian. He was sent by his uncle on a mission of uncertain date and purpose to Portugal. He was greatly beloved by Adrian, who gave him charge of the castle of St. Angelo. On the death of Adrian, Boso upheld the cause of Alexander III, who, according to Cardella, owed his election mainly to Boso's influence in the conclave. He was raised to the higher grade of cardinal-priest of St. Pudenziana by Alexander. Baronius mentions his name as one of the pope's companions on the celebrated journey to Venice in 1177. His name appears among the list of witnesses to a charter of privileges and immunities granted by Alexander III to the monastery of St. Maria in Organo of the order of St. Benedict. His signature is also attached to many bulls and other documents of the period of Adrian and Alexander (Cabdella). He died at Home in the autumn (Ciaccone), probably of the year 1181 ; for though Cardella states that his influence maimy secured the election of Lucius III (1181-82), yet his name does not appear in any of the documents of that pontificate.
Ciaccone says that he wrote several learned theological works referred to in the 'Catalogs Scriptorum Angliæ.' He certainly wrote nine poetical lives of female saints, which exist in the Cotton MSS. He was a poet of no inconsiderable merit for his time, and took care to hand down his name to posterity in his own rhymes.
[Migne's Troisième Encyclopedie Théologique, Dictionnaire des Cardinaux, vol. xxxi. ; Alonso Ciaccone (Chacon or Chaconius), Nomenclator Sanctæ Romanæ Ecclesiæ, 487, h. 16 ; Baronius (Pagius), Annales Ecclesiatici, xix. 443, 445, and Index, vol. i. ; Cardella's Memorie de' Cardinali, vol. i. ; Williams's Lives of the English Cardinals (very imperfect) ; Greenwood's Cathedra Petri.]