Double manuscript page on the Sforza monument
by LEONARDO da Vinci, Red chalk on paper, 21 x 30 cm
The impressive red chalk drawing on the right page (Codex Madrid I, fol. 157r) shows the head and neck sections of the negative mold for the bronze casting, which was reinforced by fittings. On the neck and lower side of the head one can see how Leonardo subdivided this negative mold in order to simplify taking it off after the casting was complete. On the left page technical details are illustrated.