as well as Leonardo's earlier Portrait of a Musician, due to the three paintings including black backgrounds. Though there are a few areas of minor damage, art historian Frank Zöllner insists the work is in "very good condition... similar to the equally well preserved Mona Lisa". Such an evaluation is relatively recent, however, as the work was previously considered to be considerably damaged and repainted. Promotion of such an analysis largely began with the art historian Kenneth Clark, who asserted in 1961 that the entire left side of the figure, as well as the background had been repainted. Scholars such as Adolfo Venturi, Angela Ottino della Chiesa and Jack Wasserman advanced the idea; however, a 1992 technical analysis at the National Gallery of Art led by David Bull has confirmed that the damage was limited to the background. Specifically, the background was likely originally a bluish-grey, overpainted with black during the mid-18th century. The signature LEONARD D'AWINCI in the top left corner was probably also added at this time. There is also slight overpainting in the mouth and nose; some art historians suggest Eugène Delacroix was responsible for the overpaint in the background and elsewhere. The background was also subject to the misconception that it originally included a window. It was proposed by , who led 1955 X-ray testing at Warsaw Laboratories, and explained certain spots in the right background as being remnants of a window. Such a conclusion has been disproven by Bull, Pietro C. Marani and others. In light of this revision—with the primary damage being overpaint in the background—the art historian Martin Kemp noted that "the picture is in much better condition than the standard accounts suggest, and gives the clearest indication of the freshly brilliant quality of Leonardo's painting during his period at the Sforza court in Milan". The Lady The subject has been identified with reasonable certainty as Cecilia Gallerani, the mistress of Leonardo's Milanese employer, Ludovico Sforza. She looks to her left at something out of frame, toward the light, where the biographer Walter Isaacson suggests Ludovico is. Following the marriage of Isabella of Aragon, Duchess of Milan and Gian Galeazzo Sforza, her 'Spanish style' dress would have been particularly fashionable. She has a silk sbernia on over her left shoulder, though Leonardo has simplified the traditional manner of wearing—where it would be draped over both shoulders—potentially to avoid too much complication in the