PRIERIAS, SILVESTER (SILVESTRO MAZZOLINI): Italian Dominican and opponent of Luther; b. at Priero (40 m. w. of Genoa) about 1456; d. at Rome at the beginning of 1523. He entered the Dominican monastery of Santa Maria di Castello in Genoa at the age of fifteen, and eight years later was ordained priest. From 1490 to about the end of the century he was studying and teaching at Bologna and Padua, and after being prior of several monasteries was vicar general of the province of Lombardy (1508-10), being at the same time inquisitor in Brixen and vicinity. In 1511 he became inquisitor in the district of Milan, and two years later was prior at Cremona. Meanwhile he had written a series of theological works including his Compendium Capreoli (1497), Tractatulus de diabolo (1502), Aurea rosa (1503), Tractatus de expositione missœ (1509), Malleus contra Scotistas (1514), and especially his Summa summarum quœ Silvestrina dicitur (Bologna, 1515; reprinted forty times), a work neither balanced nor original, but a comprehensive practical theology. It brought him the fame of an erudite Thomist, and about the middle of 1514, Pope Leo X. called him to Rome to take the Dominican chair of Thomistic theology at the Gymnasium Romanum; and in the following year, through the influence of Cajetan (q.v.), he was appointed master of the sacred palace. Thus he became a councilor of the pope in matters of faith and inquisitor within the city, and was also empowered to act as inquisitor and judge in matters of faith affecting the entire Church. He was influential in securing the condemnation of Reuchlin. As censor he considered the theses of Luther and within three days composed his Dialogus in prœsumptuosas Martini Lutheri conclusiones de potestate papœ (1518). Without having an inkling that it was a religious question with Luther, Prierias, in order to draw out Luther's fundamentals, set forth in four theses the most extreme views on the infallibility of the Church, concluding that anyone asserting that the Church could not do what she did (specifically regarding indulgences) must be adjudged a heretic. Luther, who received this trivial work in Aug., 1518, wrote a reply in two days, while Prierias answered briefly in his Replica (1519?) and the German reformer scornfully advised Prierias in a letter now lost not to make himself ridiculous. Prierias, who had meanwhile been officially commissioned to examine Luther's utterances, published, in 1519, an Epitoma responsionis ad Martinum Lutherum (Perugia, 1519), which was, in short, an index of the contents of a comprehensive work which he had meanwhile begun and which appeared as Errata et argumenta Martini Luteris recitata, detecta, repulsa et copiosissime trita (Rome, 1519). This was to prove that the papal decision in matters of faith and doctrine was divinely inspired and could be rejected only under penalty of eternal death. Luther published this work, like its predecessors, with a violent preface and appendix, and caustic marginal comments. He could even be half doubtful whether Prierias' statements really represented true Roman doctrine; but Leo X. declared, in a brief of July 21, 1520, that Prierias had written canonically against Luther, and threatened with excommunication and heavy fine any unlicensed reprinting of the work. It always remained an important document for the Roman Catholic doctrine of the period concerning the powers of the pope. Such was the influence of Prierias that Erasmus was forced, despite his hatred of him, to take refuge with him from the Carmelites of Louvain. Other works are Conflatum ex Sancto Thoma (with a list of his own writings; Perugia, 1519); and De strigimagarum dœmonumque mirandis libri tres (Rome, 1521).