Mantuan, active c. 1483 - c. 1526
Ruberto, Gianfrancesco , Ruberti, Giovanni Francesco
Ruberti has been identified as a young goldsmith first mentioned in Mantua and called gentil maestro on 12 February 1483. He was then recorded as working on arms intended as a gift to the Sultan of Turkey, and as beginning to strike coins by an improved method in March 1492. He was sent to Milan in 1517, and to Venice in 1497 and 1526; was recorded as master of the mint at Mantua; and continued to work for the court until at least 1526.
The medal of Francesco II (NGA 1957.14.663.a,b) is the only medal signed by Ruberti. A large group of plaquettes, signed IO.F.F., formerly was ascribed to the artist.
 Antonino Bertolotti, Artisti in relazione coi Gonzaga duchi di Mantova nei secoli XVI e XVII, Mantua, 1885: 89; Antonino Bertolotti, "La arti minori alla corte di Mantova." Archiv 15 (1888): 274, 276, 277, 192, 302.
 John Pope-Hennessy, Renaissance Bronzes from the Samuel H. Kress Collection: Reliefs, Plaquettes, Statuettes, Utensils and Mortars, London, 1965: nos. 97-110; Terni di Gregory, "Giovanni da Crema and his Seated Goddess," The Burlington Magazome 92 (1950): 159-161; Christopher B. Fulton, "The Master IO.F.F. and the Function of Plaquettes," Studies in the History of Art, 22 (Italian Plaquettes, ed. Alison Luchs) (1989): 156 n. 3, rejects the attribution.