Bernardi, Giovanni Desiderio
Giovanni da Castelbolognese
Bernardi da Castel Bolognese, Giovanni
Castelbolognese, Giovanni da
Giovanni Desiderio Bernardi, born at Castel Bolognese, was the son of Bernardo Bernardi (1463-1553), who is known to have been a goldsmith. Giovanni became the most celebrated maker of engraved plaques of rock crystal of his period and he also produced a few medals. During his apprenticeship under his father he worked for Duke Alfonso I d'Este on engraved rock crystal, and medals of Alfonso are attributed to him. Vasari records and praises a medal for the duke with a reverse of the Betrayal of Christ and a medal for Cardinal Ippolito de' Medici, which are not known. Giovanni moved to Rome at the suggestion of Paolo Giovio to work for the Cardinal Ippolito de' Medici, Giovanni Salviati, and Cardinal Alessandro Farnese. Through these connections Bernardi came to be employed by Pope Clement VII. In 1530 Bernardi produced a medal for the coronation of the Emperor Charles V at Bologna by Pope Clement and was invited by the emperor to work at the Hapsburg court. Bernardi was appointed engraver at the papal mint between 1534 and 1538, and 1541 and 1545.
His principal surviving work is the suite of engraved rock crystals, designed by Pierino del Vaga, that ornament the Cassetta Farnese, now in the Museo Nazionale, Naples. A total of forty-four engraved rock crystals are signed by or ascribed to Bernardi and many of his crystals were reproduced in plaquettes; two of them as gold foil reliefs.
[Published in: John Graham Pollard. Renaissance Medals. The Collections of the National Gallery of Art Systematic Catalogue. 2 vols. Washington, 2007]
 For the works on crystal see Ernst Kris, Meister und Meisterwerke der Steinschneidekunst in der italienischen Renaissance, Vienna, 1929: figs. 228-250, pls. 55-71. Valentino Donati, Pietre dure e Medaglie del Rinascimento. Giovanni da Castel Bolognese, Ferrara, 1989, ascribes forty-four engraved crystals, some signed, to Bernardi.
 Vasari, ed. Milanesi, 5 (1880), 371-372.
 There is a gold foil relief on jasper of the Emperor Charles V at Tunis in the Czartoryski Collection, Cracow. It is not recorded by Valentino Donati, Pietre dure e medaglie del rinascimento. Giovanni da Castel Bolognese, Ferrara, 1989.
 John A. Gere, "Two late fresco cycles by Perino del Vaga: the Massimi Chapel and the Sala Paolina," The Burlington Magazine 102 (1960): 13-14 (on the drawings for the rock-crystal plaques).