Francis Bacon at London's Tate Gallery

Head VI, 1949
Oil on canvas
Inspired by the great Velazquez Portrait of Pope Innocent X, Bacon began a long series of screaming Popes in the late '40s. Trapped in a kind of isolation booth, where a thunderstorm of granular black strokes rains down on him, this Pope suggests the baying, baboon madness of authority. (One source for the painting was a photo of Joseph Goebbels in full harangue.) Yet at the same time, he's the face of the powerlessness that sometimes even absolute power must endure.

• Francis Bacon: Tragic Genius