Le Chef-d’œuvre inconnu (English The Unknown Masterpiece)

is a short story by Honoré de Balzac. Young Nicolas Poussin, as yet unknown, visits the painter Porbus in his workshop. He is accompanied by the old master Frenhofer, who comments expertly on the large tableau that Porbus has just finished. The painting is of Mary of Egypt, and while Frenhofer sings her praises, he hints that the work seems unfinished. With some slight touches of the paintbrush, Frenhofer transforms Porbus's painting such that Mary the Egyptian appears to come alive before their very eyes. Although Frenhofer has mastered his technique, he admits that he has been unable to find a suitable model for his own masterpiece, which depicts a beautiful courtesan called Catherine Lescault, known as La Belle noiseuse...