Head of Medusa

For more than a century this severed head hung in the Uffizi as a Leonardo. The mistake began in 1782, when Luigi Lanzi, who was cataloguing the gallery's Leonardos, matched it to Vasari's story that the young Leonardo once painted a monstrous head so lifelike it frightened those who came upon it. The picture in front of you is not that lost work. Scholars in the 20th century, Bernard Berenson among them, gave it back to an unknown Flemish painter working around 1600, who studied real snakes and rotting flesh to get the writhing detail right. It had entered the Medici collection in 1668, where it was kept behind a small curtain of shot silk and shown only to chosen visitors, so drawing the cloth aside became part of the shock. The snakes are still doing the work the curtain once framed.