Vieillard was the son of Antoine Vieillard de Boismartin, a lawyer at the Parlement of Rouen, then mayor of Saint-Lô, known for his beautiful and generous defense of the Verdure family (1780-1789), earning him the direct praise of Louis XVI, to whom he was introduced, and a kind of civic ovation in the midst of the National Constituent Assembly, during the session of January 30, 1790.
He also became one of the principal editors of the Encyclopédie des gens du monde, where he was specially commissioned to write biographies about famous men of the French Revolution.
Well versed in the history of that time, which he lived, the moderation of his opinions and the uprightness of his character let him naturally assess accurately the events and actors.
Thus he could believe he was authorized to contribute the Le Moniteur Universel a series of studies on the Girondins [fr] by Lamartine, a work interrupted by the Revolution of 1848.
Méhul, Madame Scio, Vicissitudes d’un librettiste de l’ancien opéra are the titles of these curious and interesting studies reproduced by le Ménestrel.