on tablet above bust, in raised relief: S A C 
 The letters probably signify one or more of the following related concepts: sacellum (shrine); sacra (sacred); sacrata (made holy, inviolable, or immortal); sacramentum (oath); sacrarium (sacristy or shrine); sacrificatio (sacrificing); sacrificium (sacrifice); sacrum (holy thing or place). The last concept listed, sacrum (holy thing or place), was the interpretation proposed in the first publication of the plaquette, in Bernardus de Montfaucon, Antiquity Explained, and Represented in Sculptures, Translated by David Humphreys, 2 vols., London, 1721: 2:158: "The little brazen Plate of Sir Edward Fountain...seems...to be a Vow made to some Divinity; and which the Inscription S A C, signifying Sacrum, puts beyond doubt."
The letters have also been suggested--perhaps still plausibly, in a double meaning--as possibly a unique version of the artist's signature, in the form Sculpsit Andreas Crispus (modeled by Andrea Crispo, i.e., Riccio). This reading was hypothesized in the NGA acquisition proposal of 16 August 1984, written by NGA curator Douglas Lewis and NGA curatorial assistant Christopher B. Fulton. Shelley Sturman and Barbara Berrie ("Technical Examination of Riccio Plaquettes," in Italian Plaquettes, Center for Advanced Study in the Visual Arts, Symposium Papers 9, Studies in the History of Art 22 (1989): 188 n. 7) reported the formulation as that of Fulton alone (presumably because he had typed and initialed the proposal).
(sale, Christie, Manson & Woods, London, 13 April 1983, no. 99); (unknown dealer); (Ellin Mitchell, New York); purchased 6 November 1984 by NGA.
- Renaissance and Baroque Bronzes, Milwaukee Museum of Art, Wisconsin, 1989, brochure no. 8.
- Sturman, Shelley and Berrie, Barbara. "Technical Examination of Riccio Plaquettes." Studies in the History of Art 22 (1989):180-181, 186-187, repro.
- Lewis, Douglas. "Collectors of Renaissance Reliefs: Erasmus of Rotterdam (1466-1536) and Baron Boissel de Monville (1763-1832)." In Collecting Sculpture in Early Modern Europe. Ed. by Nicholas Penny and Eike D. Schmidt. Studies in the History of Art 70, Symposium Papers XLVII (2008): 137-138, 143 n. 42.