These marble portrait busts were not intended as a pendant pair, but when displayed together they reveal a family resemblance--these are sisters. The elder, Brigitte Garnier d'Isle, alert and dignified, turns to her left with a far-off gaze. The younger Adélaïde very much resembles her elder sister, but her gaze is more immediate, her face more exuberant and her pursed lips seem to barely suppress a grin. Each sister displays a fashionable hairstyle, composed of tight waves of hair, and wears a loose shawl. Adélaïde's slightly more revealing drapery is knotted at her breast, reflecting her relative informality.
Brigitte and Adélaïde were the daughters of the architect Jean-Charles Garnier d'Isle, who shared a personal and professional relation with the sculptor Jean-Baptiste Pigalle. Garnier d'Isle designed the château and gardens of the lavish Bellevue estate of Madame de Pompadour, the mistress of Louis XV. Probably on the recommendation of Garnier d'Isle, Pigalle was commissioned to create garden statues at Bellevue. Garnier d'Isle clearly admired Pigalle's intimate and unembellished portrait style. He himself sat for a portrait that Pigalle exhibited, as a plaster bust, at the Salon of 1750.