Euclid

In the 1630s, in Spanish-ruled Naples, Jusepe de Ribera hit on a strange idea, to paint the great thinkers of antiquity as if he had pulled them off the street. Here is Euclid, the mathematician whose treatise the Elements set the foundations of geometry for 2,000 years. Ribera gives him no marble dignity. He is an old man in torn clothes, emerging from deep shadow, his fingers blackened with grime, clutching a worn book of diagrams that tells us who he is. It belonged to a whole series of ragged philosophers Ribera painted in these years, when educated collectors were newly hungry for ancient wisdom. Look closely at the book: the geometric figures are real, but the Greek letters around them are invented, a convincing scribble.