The philosopher Aristotle rests his hand on a bust of the poet Homer, lost in thought. A gold chain hangs from his shoulder with a medallion of Alexander the Great, his famous pupil. Rembrandt painted it in 1653 for a Sicilian nobleman.

In 1961 the Met bought it at auction for $2.3 million, at the time the highest price ever paid for a painting. Look at the sleeves: thick, glowing paint built up in layers, against a dark background.