Three windows appear in the background of Leonardo da Vinci’s *The Last Supper*.
The windows are arranged across the rear wall behind Jesus, with the central opening directly framing his head and body. Their bright outdoor light helps make Christ the visual center of the composition, even though Leonardo does not surround him with a conventional painted halo.
The architecture also reinforces the painting’s carefully planned perspective. The room’s lines converge toward a point near Jesus, while the three openings create a balanced backdrop for the groups of apostles. The number three appears repeatedly in the design: the apostles are arranged in four groups of three, and the windows can evoke Christian associations with the Trinity.
Viewers sometimes count only the two side openings or mistake the central area for a doorway. In the painted rear wall, however, the composition presents three distinct window openings, each revealing the landscape beyond. The openings are part of the illusionistic room Leonardo created on the refectory wall of Santa Maria delle Grazie in Milan.