Task: Question Generation
Input (English):  Pierre Grassou de Foug res is a mediocre painter who lives off painting forgeries commissioned by an old swindler and art-dealer named Elias Magus. Grassou paints forgeries of works by Titian, Raphael, and other famous artists. Magus resells these forgeries for a large profit to members of the Petite bourgeoisie who are incapable of appreciating good art.
Monsieur Vervelle, a prosperous bottle-dealer obsessed with art, is introduced to Grassou by Magus, who introduces the painter as a grand master. Vervelle and his wife are enchanted with Grassou and believe he would make a good match for their daughter Virginie.
Grassou is invited to Ville-d'Avray, where the Vervelle mansion is garishly decorated, and also includes a large collection of Grassou s work, including the forgery of a Titian. Grassou recognizes his own mediocrity, but when it is discovered by the Vervelles that the forgeries in their home were painted by Grassou,  far from denting his reputation, multiples Grassou s value as an artist  and as a son-in-law, since Vervelle believes Grassou to possess all the combined talent of Rubens, Rembrandt, Terburg, and Titian.
Despite his advantageous marriage, Grassou remains bitter that he is not a true artist.  This painter, a good father and a good husband, is unable to eradicate from his heart a fatal thought, namely, that artists laugh at his work; that his name is a term of contempt in the studios; and that the feuilletons take no notice of his pictures. But he still works on; he aims for the Academy, where, undoubtedly, he will enter."
Output (English): Who are some of the artists whose work Grassou has forged?