Leonardo’s greatest work to reach completion was the Last Supper, painted for Ludovico Sforza in the monastic dining hall of Santa Maria delle Grazie, Milan. He probably began the painting after work on the Sforza equestrian monument had been suspended in 1494. The Last Supper was complete by 1498, but it was soon deteriorating, and what we see today is a ghost
of Leonardo’s intentions.

Though Leonardo must have executed many drawings as he worked out the design, only one compositional sketch survives and a few details, mostly head studies, in which Leonardo uses chalks extensively for the first time.