This essay deals with the activity of painter Franco Villoresi (1920-1975), from his beginnings in Rome in the late 1940s to his involvement as a "master" in the painting atelier for the patients of the Arezzo Neuropsychiatric Hospital, opened in 1958 by his friend Furio Martini, vice-director of the institute. Villoresi’s first works drew on Mario Mafai’s paintings, his master. Villoresi achieved expressive autonomy in the 1950s in the framework of an alienating realism, with views of suburbs and train stations in which faceless human silhouettes wander as if lost. This phase was followed by the period of the “Grandi personaggi”, a satire of the respectability and conformism of wealthy society. During his teaching in the Aretine hospital atelier (from 1958 to 1961), in contact with a sorrowful humanity unadulterated by conventions and superstructures, Villoresi elaborated the theme of the mask, which was to become the constant emblem of his painting to come in all its moral and existential implications.