Recto: indistinct studies of skirmishing horsemen and foot soldiers in violent motion. Verso: a drawing of a group of fighting horsemen, almost indistinguishable. Melzi's number 31.

Leonardo’s most ambitious painting – albeit unfinished – was the Battle of Anghiari, a mural intended to be perhaps 60 feet (18 m) wide, depicting a celebrated Florentine victory of 1440 over the forces of Visconti Milan. The painting was commissioned in 1503 by the Florentine government for the Great Council Chamber of the Palazzo della Signoria. The painting was underway by June 1505 and proceeded until the summer of 1506, when Leonardo’s temporary return to Milan was requested by the French occupiers of that city, and permitted by the Florentine government for diplomatic reasons. Although Leonardo was back in Florence at least twice in 1507 and 1508, he never resumed the painting. Only the central portion, known as the Fight for the Standard, was substantially completed and this was obliterated – or, as has been claimed, concealed – after 1563.

RCIN 912338 and 912330 consider possible figures, horses and groups for the composition. The charcoal of RCIN 912338 is heavily rubbed, but most of the motifs can be made out. From left to right we see a figure falling to the left while another lunges at him, brandishing a weapon aloft; a horse and rider galloping or leaping to the right; a rearing horse with rider, reminiscent of Leonardo’s studies for equestrian monuments; two horses clashing, their heads twisted violently away, one rider holding a lance downwards; another study of two rearing horses with their riders trading blows, and a figure running to the left. Several of these motifs have the flavour of Paolo Uccello’s three panels of the Battle of San Romano, the major Florentine precedent for a monumental battle scene.

Text adapted from Leonardo da Vinci: A life in drawing, London, 2018