Marie-Denise Gandolphe was the descendant, on her mother's side, of Jacques Daran (1701-1784), urologist and surgeon ordinary to Louis XV. Her father, Matthieu Gandolphe (1755-1804) served as advocate at the Parlement de Paris. In 1798 she married the Liège printer Jean-Joseph Smits (1756-1806), who with the voltairien Pierre-Henri-Hélène Tondu (1753-1793) had founded the Enlightenment periodical Journal général de l'Europe in 1785. Their daughter Coralie would marry Count Borchgrave d'Atlena. In 1808, after the death of Jean-Joseph, Marie-Denise married Michel-Laurent de Sélys-Longchamps; their daughter Amanda-Laurence was the mother of the celebrated Belgian activist and educator Léonie de Waha, while their son Michel-Edmond would be one of the founders of the liberal party in 1846 and president of the Sénat from 1880 to 1884.
In Paris, Marie-Denise patronised a circle of exiled Liège artists, including Joseph Dreppe (1737-1810), Henri-Joseph Rutxhiel (1775-1837) and Ansiaux himself. With her second husband she saw the reconstruction of the château of Longchamps, near Waremme in Belgium, an outstanding example of Belgian neoclassical architecture.
It is this interest which is made apparent in the present picture, which shows Marie-Denise in a thoroughly neoclassical mode; the painted decoration of the harpsichord, the design of the armchair with its winged arms and swan-shaped legs, the winged genius holding sheet music and the statue of Apollo in the background are directly inspired by Roman interior design. A pendant portrait of Jean-Joseph Smits sitting in a garden, with Coralie on his knee, remained in the family until 1987, when it was sold (Sotheby's Monaco, 20 June 1987, lot 421). In a charming conceit, the background of the pendant shows Marie-Denise looking out of the colonnaded space toward her husband and daughter as she plays her harp, as though she has just turned away from her position in the present picture and moved toward the column in the background.
Antoine Ansiaux studied under François-André Vincent (1746-1816), a leading exponent of the neoclassical style. Ansiaux entered the École de l'Académie Royale in 1783, and soon became known as a painter of historical scenes, including many for churches and other public sites: St-Étienne-du-Mont and the Hôtel de Ville in Paris, and the Cathedrals of Liège, Angers, Arras, Le Mans, and Metz. Like Ingres, greatest of the French neoclassicists, Ansiaux supplemented his history painting practice by taking commissions for portraits from prominent members of society, which he executed, like Ingres, in an immaculate Italiante style.