This is an unused frontispiece for the Spectacle de l'Histoire Romaine written by Etienne-André Philippe, called Philippe de Prétot (1710-1787) and incompletely published between 1762 and 1778. The project consisted of very precise illustrations of episodes from Roman History accompanied by a text by Philippe. The first twenty plates were announced on 18 August 1762 and the following twenty four years later. These were reprinted respectively in 1776 and 1777. Eight supplementary plates appeared slightly later.
Not only was the complete book never published, but Emile Dacier could not even find any past editions of the book. The prints are known today only through the Abrégé de l'histoire romaine by the Abbé Millot which reuses Philippe's plates. Saint-Aubin designed 28 plates for the original edition while the rest were made by J.B. Piauger, Eisen, Gravelot and a few others. The frontispiece used for Millot's edition is Piauger's, engraved by Tardieu.
The style of this drawing is comparable to one of similar technique dated 1767 in the Louvre (P. Rosenberg, Le Livre des Saint-Aubin, Paris, 2002, no. 11).