Leonardo’s greatest work to reach completion was the Last Supper, painted for Ludovico Sforza in the refectory of Santa Maria delle Grazie in Milan. This revolutionary exercise in the depiction of emotion shows the reaction of the Disciples to Christ’s announcement of his imminent betrayal.

Leonardo must have executed hundreds of drawings as he refined the composition, but only one compositional sketch survives and a handful of details, mostly head studies. He probably started to paint the mural after work on the equestrian monument to Francesco Sforza had been suspended in 1494. The Last Supper was complete by 1498, but Leonardo’s experimental technique – combining oil, tempera and varnish – was soon deteriorating, and what we see today is a ghost of his intentions.