Catholic Encyclopedia (1913)/Justus Baronius Calvinus
A convert and apologist, b. at Kanthen, Germany, c. 1570; d. after 1606. He was born of Calvinist parents and educated at Heidelberg where he took a course in theology. His study of the Fathers inclined him towards Catholicism and finally led him to Rome where he was kindly received by Cardinals Bellarmin and Baronius and by Pope Clement VIII. The writings of Bellarmin strengthened his conviction regarding the Church, and his gratitude to Baronius caused him to add that cardinal's name to his own. On his return to Germany he became a Catholic (1601) and a staunch defender of the Faith. In his "Apologia" (Mainz, 1601) he gives the reasons for his conversion and in his "Praescriptionum adversus haereticos . . . Tractatus" (ibid. 1602, 1756) he appeals to the Fathers in support of the truth of Catholicism.