**PIETRO DA PIETRASANTA**
Silvestro Pietrasanta. - Jesuit apologist and scholar, born in Rome in 1590, died there on 1/8 May 1647. He successively served as professor of Literature in Fermo, theologian to Monsignor Luigi Carafa, Apostolic Nuncio to Cologne, and Apostolic Visitor of the Piarist Institute. He was unjustly accused of playing a significant role in the internal difficulties that troubled the Piarists after the Apostolic Visitation. He introduced the use of lines and points indicating colors in noble coats of arms.
Among his numerous writings, the following are noteworthy: *Racconto dell'elezione di mons. G. F. Greiffenclas in arci di Magonza* (Liège 1626); *Iter fuldense* (ibid. 1627); *Iter moguntinum* (ibid. 1629); *Legatio apostolica A. Carafae* obita ad tractum Rheni (ibid. 1634): these works are of particular interest for the religious history of Germany; *Notae in epistolam Petri Molinae ad Balzacum* (Antwerp 1634); *Calvinianus Verbero et in eum vindiciae vapulare* (Loreto 1639); *Breve esplicazione delle litanie della B. V.M.* (Rome 1643); *Thaumasia verae religionis contra perfidiam sectarum* (2 vols., Rome 1655).
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**PIETRO D'ALCANTARA, MARTYR**
Pietro d'Alcantara, martyr. - Head of the catechetical school of Alexandria, he became bishop of that city in 3000. His flight during Diocletian’s persecution caused the Meletian schism. P. died a martyr in 311.
Only fragments of his writings survive, the most important being the 14 penitential canons. The Acts of his martyrdom are legendary.
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**PIETRO ALFONSO**
Pietro d'Alfonso. - Jewish physician (Mose Sephardi), born in Huesca (Aragon) in 1062, converted at the age of 44, died c. 1110. A profound scholar of the Bible and Arabic thought, he was baptized by Stephen, bishop of Huesca, on 29 June 1106 and took the surname of Alfonso VI, King of Castile and León, who stood as his godfather and retained him as his physician (P. calls him his “spiritual father”).
To vindicate the biblical foundations of his conversion against the slanders of his former coreligionists, he set forth the circumstances (in the *Prologus*) and reasons in the 18 dialogues *Petri cognomento Alphonsi ex iudaeo christiani Motysi iudaei* (the author before conversion): “Mose” raises objections and “Alfonso” resolves them. The work, written in an engaging style, is erudite, methodical, and of great interest for understanding anti-Christian conceptions (especially in the early dialogues) and the formalism of 12th-century Jews; it played a significant role in the apologetics of the time. It is praised by R. Martini (*Pugio fidei*, III, 3,4), Vincent of Beauvais (*Spec. hist.*, XXV, 118), and Matteo Palmieri (*Cronaca*, 1068). Perhaps the anti-Christian writings of R. Jacob ben Ruben (*Milhamoth 'Adhōnaj*, 1170) and R. Shēmōthō ben Jishāq of Tudela (*'Ebbien bōhen'*) were intended as replies to P. It was printed in Cologne (1536), then in PL 157, 535-672. P. also composed the didactic-moral work *Disciplina clericalis*, in a prologue and 30 fables drawn from Arabic authors, inserted into a dialogue between a dying Arab and his son; various 14th-century novellists drew upon II. It was published (2 vols., Paris 1824) by J. Labouderie, vicar general of Avignon, who added two ancient French vernacular versions, one in prose (15th c.), the other, older, in verse; P.’s text is reproduced in PL 157, 671-706.
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**PIETRO D'AUVERGNE**
Pietro d'Auvergne. - A disciple of St. Thomas Aquinas in Paris, he first served as a master in the Faculty of Arts, then studied theology under Henry of Ghent (v.) and Godfrey of Fontaines. He became a master in theology around 1296, and at that time or shortly thereafter composed his *Quodlibeta*. Bishop of Clermont from 1302, he died in 1304.
He completed St. Thomas’s commentary on *De caelo*, the *Politics*, and partially on the *Meteorology*. Yet, as a master of arts, he also wrote his own commentary on the *Politics*. He authored *Quaestiones in Metaphysicam* and works on the *Parva naturalia*. In this first period of his teaching, he was under the direct influence of monistic Aristotelianism (v.). In a second period, the monistic influence was partly neutralized by that of his theology teachers, especially Godfrey, e.g., regarding the principle of individuation (v.), the distinction between essence and existence, and the relationship between intellect and will (v.).