Considered to be, with good reason, the most beautiful nude in nineteenth-century Spanish painting, this work provides eloquent testimony of the modernity that made Rosales stand out in the Spanish artistic panorama of his time. He would have earned himself a prominent place among the era´s artistic vanguard in Europe if his brilliant career had not been cut short by his premature death. Neither a mere sketch nor academic study, this painting is an intentionally unfinished work. Rosales´s approach in this canvas is unusually daring in formal terms, his pictorial language is vehement, sincere and audacious, and the painter seems to seek the greatest possible expressiveness of pure painting. With a restrained colour palette, drawn from pinks and carmines that contrast with the greenish tones so characteristic of his oeuvre, Rosales took full advantage of paint´s substance, combining markedly impastoed zones with others in which the greyish preparatory layer of the canvas is visible. In addition, using the handle end of his paintbrush he traced lines into the paint to mark the hair, and used pigments with the fluidity of watercolour for other areas, allowing them to drip down the canvas in a fearless approach to the medium that is truly astonishing. Such an approach would not become common in Spanish painting until almost Joaquín Sorolla´s time.On the other hand, the simplicity of the composition -in which the model´s luminous nude body is perfectly framed by the space surrounding her, suggested by a few lines- reveals the astounding conceptual shift that Rosales represents among the painters of his generation and his decisive role in leading his contemporaries in Spain toward modern painting.Even more surprising is how Rosales demonstrated his sensibility as an artist by capturing on this canvas -despite its extremely agile, synthetic technique- the palpable, carnal sensuality of the female form, transferred to the painting with absolute honesty and without any idealisation or artifice. Thus, he models the volume of her body -round and full, with command of the light that shines from the left- sculpting it with large spaces of colour, executed in energetic, confident brushstrokes, without hesitation or retouching. The model, withdrawn into her own world, dries her skin, her back to the viewer. Rosales highlights her pale complexion in the half-light of the room and marks the sinuous contours of her long legs and wide hips through long, continuous brushstrokes that coolly underscore the erotic charge of an otherwise modest pose.This work was painted in Rome in a single day. Apparently, Rosales´s usual model, Nicolina, posed for this work, although the figure in the painting also bears a striking resemblance in terms of posture and anatomy to the sculpture by the German Reinhold Begas (1831-1911), After the bath (Nach dem bade) 1861, which Rosales would have seen in Rome (now in the Hamburger Kunsthalle, Germany).The absolute freedom in its execution and, indeed, the very subject of the canvas, suggest its intimate, reserved character. It remained in Rosales´s studio until his death in 1873 (Díez, J. L.: Portrait of Spain. Masterpieces from the Prado, Queensland Art Gallery-Art Exhibitions Australia, 2012, p. 264).