Perspective Study for the Background of the Adoration of the Magi

In 1481 the monks of San Donato, a monastery just outside Florence, hired Leonardo to paint an Adoration of the Magi for their altar. This small sheet is him building the stage for it. He ruled a precise floor grid running back to a single vanishing point, then set a ruined building, a staircase, arches, horses and tiny figures onto it, everything shrinking at exactly the right rate as it recedes. It is a piece of geometry as much as a drawing. Look at the panel it was made for, hanging in the same museum, and the plan survives in the broken architecture behind the crowd. Leonardo never finished that painting. In 1482 he left for Milan and the altarpiece stayed a brown underdrawing, while behind the figures the same receding arches are still faintly there.