Titian: Gods and Emperors: Venus of Urbino, 1538 #40/50

Delivered in 1538 to Guidobaldo della Rovere, later Duke of Urbino. A goddess or a courtesan — Titian never said, and the argument has run for five centuries. Manet answered it with Olympia, Mark Twain called it the filthiest picture in the world, and almost every reclining nude in Western art traces back to it. Galleria degli Uffizi, Florence.