Sylvester Mazzolini, in ItalianSilvestro Mazzolini da Prierio, in LatinSylvester Prierias. was a theologian born at Priero, Piedmont; he died at Rome. Prierias perished when the imperial troops forced their way into the city, leading to the Sack of Rome. At the age of fifteen, he entered the Dominican Order. Passing brilliantly through a course of studies, he taught theology at Bologna, Pavia, and in Rome, whither he was called by Julius II in 1511. In 1515, he was appointedMaster of the Sacred Palace, filling that office until his death. His writings cover a vast range, including treatises on the planets, the power of the demons, history, homiletics, the works of St. Thomas Aquinas and the primacy of the popes. His exposition of Thomas' teaching was critical of the interpretations offered by his fellow Dominican Thomas de Vio Cajetan. Prierias is credited with being the first theologian who by his writings attacked publicly the doctrines of Martin Luther. Johann Tetzel's productions against the arch-reformer are called by Jacques Echardscattered pages, and Mazzolini stands forth as the first champion of Romen Pontiffs against Luther. Luther replied to Mazzolini's arguments and the latter published rejoinders, and there was a regular controversy between them. According to D.J. Kennedy’s article in the Catholic Encyclopedia, ‘the necessity of promptness in attack and defence will account for defects of style in some of his writings’. Morgan Cowie is blunter on his performance in the controversy with Luther: ‘he succeeded so ill that the Pope forbade him to write any more on the matters in discussion’. He further notes that the eighteenth-century Jesuit literary criticGirolamo Tiraboschi ‘is rather annoyed that Erasmus speaks ill of our author as a controversialist, but is compelled to allow it to be true.’ His principal works are: De juridica et irrefragabili veritate Romenæ Ecclesiæ Romenique Pontificis ; Epitoma responsionis ad Lutherum ; Errata et argumenta M. Lutheri ; Summa Summarum, quæ Sylvestrina dicitur, reprinted forty times; an alphabetical encyclopedia of theological questions; Rosa aurea an exposition of the Gospels of the year; In theoricas planetarum.