This work and its variant in the Musée d'Orsay, Paris, represent the most ambitious paintings Degas devoted to the theme of the dance. Some twenty-four women, ballerinas and their mothers, wait while a dancer executes an "attitude" for her examination. Jules Perrot, a famous ballet master, conducts the class. The imaginary scene is set in a rehearsal room in the old Paris Opéra, which had recently burned to the ground. On the wall beside the mirror, a poster for Rossini’s Guillaume Tell pays tribute to the singer Jean-Baptiste Faure, who commissioned the picture and lent it to the 1876 Impressionist exhibition.