In 1800, a flood covered the floor of the refectory to a depth of two feet, and when the waters subsided, the painting was covered with a thick mould. The picture has also suffered from the injudicious restorers who, from 1726 to 1870, imposed their own conceptions of coloring upon Leonardo’s masterpiece. Since then, the main effort has been directed toward removing all traces of the work of the restorers so that we can get, if only faintly, the original picture. We can get a very good conception of the original composition, if not of the harmony and coloring, from the excellent engraving of Rudolf Stang of Düsseldorf, who after thirteen years of study published an accurate engraving. Especially good, also, is the engraving bearing the mark of Raphael Morghen.