Sisyphos

Titian painted this around 1548, while he was in Augsburg working for the emperor Charles V, not long after Charles had crushed a revolt of German Protestant princes at the battle of Muhlberg in 1547. The commission came from the emperor's sister, Mary of Hungary, who ruled the Netherlands for him. She wanted a set of four huge canvases showing famous sinners of Greek myth punished forever in the underworld, and she hung them in the great hall of her palace. The message to any nobleman who might think of rebelling was not subtle. Here is Sisyphus, condemned to shoulder an enormous boulder uphill for eternity, straining under a weight that will always roll back down. Philip II of Spain later inherited the series, which is how it reached Madrid.