17th-century Rome was fighting a war: the plain chapels of Protestantism were pulling believers away from southern Europe. The Church called in Caravaggio, Bernini and Rubens — and the solution they invented was to shoot the miracle like a movie.

From then on, ‘art’ gained a new rule: the viewer must be stunned first, and only then begin to think. That rule runs straight through to today’s Hollywood, the Apple keynote, and every visual design that wants to persuade you.