CALVINUS, JUSTUS. – Controversialist, born at Wetter (Hesse) in May 1572, died at Mainz between 1616 and 1621. While attending the theology course at Heidelberg, he happened to read the Annals of Cesare Baronio, which were being published precisely at that time. That reading and the study of the Fathers, around the year 1600, the Holy Year, enlightened him and brought him into the orbit of Catholicism, through the correspondence then deliberately initiated between him, a seeker of truth, and Baronio, who became his amiable, patient, and attentive teacher and spiritual guide. This correspondence is today a precious relic of the Vallicelliana Library in Rome (cf. cod. Vallicelliano Q. 47, fol. 117 ff.).
Having gone to Rome to visit the holy city and his spiritual benefactor (1601), C. was confirmed in the Lateran Basilica by Clement VIII himself, with Cardinal Baronio as his godfather. Out of deferential gratitude, Giusto C. then also wished to assume the surname of the cardinal (Baronio). The cardinal overwhelmed him with attentions and admitted him among
CALZARI — On the left: pontifical stocking (13th century) — Delsberg, Sacro Museum. On the right: pontifical stocking of Cardinal Arnoldo de la Vie (d. 1335) — Paris, Cluny Museum.
and kept him among his household for four months. On returning to his homeland, he provided him with a letter of recommendation for the prince-elector Archbishop of Mainz. It begins as follows: «He who came from Mainz to Rome, Giusto C., now returns from Rome to Mainz as Giusto Baronio».
The newly converted man graduated from the Italian universities of Perugia and Siena and then, back in his homeland, recounted his conversion in a volume, Apologia (Mainz 1601). He also wrote Prascriptionum adversus hareticos... Tractatus (ibid. 1602 and 1756) and De falso Jubilaeo Wittenbergensi adversus Aegidium Junium Lutheri discipulum and, upon the death of Cardinal Baronio, a funeral Elogio funebre for him, which he sent to Nicola Serrario, the Lorrainer Jesuit and friend of Baronio himself.