Beginning in 1891, shortly after his engagement, Denis made Marthe the most frequent subject of his paintings; she was depicted, in purified and idealized form, doing household tasks, taking naps, and at the dining room table. She appeared in his landscapes, and in his most ambitious works of the time, The series called "The Muses", which he began in 1893, and showed at the Salon of Independents in 1893. He sold the first painting to his friend Arthur Fontaine; In 1899 The French state acquired one of the paintings, his first official recognition.