The story of Apelles and Campaspe is recounted in Pliny the Elder's Natural History (35:10-36). It tells how Apelles was asked by the Emperor to paint a portrait of his favourite 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. For centuries, the romantic tale of Apelles and Campaspe provided a means by which painters could praise their courtly and noble art. Apelles of Kos himself was celebrated as the most gifted artist of the ancient world, with an unrivalled ability to create likenesses. Pliny wrote that 'he singly contributed almost more to painting than all the other artists put together' (35: 79).
This is the earliest of Tiepolo's treatments of this subject - a great reflection on the art of painting itself - and dates from the early- to mid-1720s. The design was adapted for a larger picture of the later 1720s, now in the Montreal Museum of Fine Arts (A. Morassi, A Complete Catalogue of the Paintings of G.B. Tiepolo, London, 1962, pp. 29-30): the positions of the artist, his head now turned to look backwards at Campaspe, and table are moved to the right, but the setting is little changed, with fluted pilasters, a different statue turned in the other direction, and the Palladian arcade of a type so loved by Veronese; the pictures in the painter's studio - Venus, and the Brazen Serpent in this canvas - are, however, changed. Campaspe, her face still in profile, is reversed and Alexander sits at her side, a less adolescent and more consciously heroic figure. Tiepolo's last picture of the subject, which measures 42 by 54 cm. and is thus similar in scale to the present canvas, was sold, Christie's, New York, 27 January 2000, lot 82 ($2,000,000) and is now in the J. Paul Getty Museum. It is generally thought to date from the late 1730s and is radically different in composition. Nonetheless Tiepolo clearly took his earlier pictures as points de départ for, apart from such necessary details as the easel, the background elements depend on these: the fluted pilasters become fluted columns, while the arcade is more elaborate and enriched with sculpture. Despite its intimate dimensions this, Tiepolo's first rendition of the subject, is thus a revealing link between the formative phase in the 1720s, when Tiepolo emerged as the most versatile Venetian master of the younger generation, and the period of his full maturity.
Morassi suggested that, in this picture, the painter portrayed himself, with his wife Cecilia Guardi - and the angle of the head would indeed be possible for a self-portrait - but Christiansen considers that such a claim can only be convincingly made for the Montreal picture.