The sitter is Françoise Marie de Bourbon, known as Mademoiselle de Blois (1677-1749), the legitimized daughter of Louis XIV by his mistress, Madame de Montespan. The identification is borne out by comparison with two portraits of her by unknown artists in the Musée National du Château de Versailles (see P. Gaxotte, Louis XIV, Paris, 1974, p. 285 and T. Bajou, La Peinture à Versailles, XVIIe siècle, Paris, 1998, p. 277).
In the present composition, Mademoiselle de Blois appears as a triumphant Galatea. Watching her is the Cyclops, Polyphemus, who had attempted to seduce the sea nymph by playing on a reed-pipe, an ancient symbol of lust. In one version of the story he succeeded, whereas, according to Ovid's Metamorphoses (XIII, lines 750-897), she preferred the handsome Acis, whom Polyphemus later killed in a fit of jealous rage.
The portrait may have been painted to commemorate her marriage on 18 February 1692, to her cousin, Philippe de Bourbon, Duc de Chartres (1674-1723), the future Duc d'Orléans and Regent of France.