Giovanni Antonio Pantera, cathedral canon and archpriest of the Poreč Cathedral of the Assumption of Mary, was one of the most prominent members of the clergy of the Diocese of Poreč in the 16th century. He is the author of Della monarchia del Nostro Signore Gesù Christo, which from 1545 to 1586 had as many as 12 editions. But because the author was included on the “List of Forbidden Books,” the interest in his work waned at the turn of the century. The article draws attention to the, so far in the literature, unknown translation of this work into Spanish, written by the Carmelite Pedro de Padilla, which was printed in Valladolid in 1590. In addition to the above, the article presents hitherto unknown data about the Archpriest of Poreč based on the archives of the Poreč Chapter from the 18th century and notarial records of Giacomo dal Bò and Antonio Torello from the State Archives in Pazin.