Each of the present cabinet plates depicts an image steeped in allegorical imagery. For example, the plate after Giambattista Tiepolo of Alexander and Campaspe in the studio of Apelle celebrates a painter of the Ancient World, the court painter to Alexander the Great, who forbade any other artist to draw his image. So great was the artist's ability to recreate a living likeness, it was said, that horses would neigh as they passed the painted horse in his equestrian portrait of Alexander and birds would try to pluck the fruit from his still-lifes.
The elder Pliny recounts in his Natural History (35:10-36) how Apelles was engaged by the Emperor to paint a portrait of his favorite concubine, the beautiful Campaspe, and how, while working on the commission, the artist fell in love with his sitter. In appreciation of the painter's work, Alexander gave Campaspe's hand to Apelles in marriage. From the Renaissance through to the eighteenth century, the romantic story of Apelles and Campaspe provided a conventional subject by which painters could praise their courtly and noble art.
See Sheila K. Tabakoff, Le Porcellane di Vienna a Palazzo Pitti, Firenze, 2002, p. 208, fig. 134 for a pair of Vienna vases and covers in the Palazzo Pitti painted with Hylas and the Nymph.