Varrone or Varro was a natural son of a Florentine, Angelo Belferdino, and is documented as working in Rome between 1450 and 1457, making marble windows for the old Saint Peter's in 1450 and bronze doors for the Castel Sant'Angelo in 1454. He was also active in Rome before the date of those documents, having been principal assistant to Filarete during the production of the doors for Saint Peter's, made in 1445, and appearing in the scene of Filarete and his assistants on the back of the doors. He is identified in the scene as "Varrus florenti" and is placed immediately after Filarete himself, as the principal assistant.
The artist who signed the medal of the Emperor Claudius (NGA 1988.30.1.a,b) was hitherto unknown as a medal maker. A second medal, of Marcus Croto, is now attributed to him (NGA 1957.14.798.a,b), and a third medal, of an unknown woman, has recently been attributed to him.
 John R. Spencer, "Filarete's Bronze Doors at St. Peter's," in Collaboration in Italian Renaissance Art, eds. Wendy Sheard Stedman and John T. Paoletti, New Haven and London, 1978: 33-57. Spencer ("An Unknown Fifteenth-Century Medallist, Varro, Beltrame Belfradelli," The Medal no. 13 (Autumn 1988): 4-7) originally identified Varro as Beltrame Belfradelli; Louis Waldman, "Varrone d'Agniolo Belferdino's Commemorative Medal of an Unknown Lady," American Journal of Numismatics 3-4 (1991-1992): 105-116, has discovered documents that give his name as Varrone Belferdino.
 Waldman 1991-1992.
[This is the artist's biography published in the NGA systematic catalogue of Renaissance medals.]