Pieter Lastman, 'Juno discovering Jupiter with Io', 1618

Jupiter, ruler of the Roman gods, fell in love with Io, a young human woman, and seduced her. Interrupted by Juno, his wife, he hastily changed Io into a cow. Pieter Lastman has shown Jupiter, still naked, looking up with startled eyes at the enraged Juno, who arrives accompanied by the peacocks that are her attribute.

Two figures pull back a wine-coloured cloth from the head of the transformed Io. One is Cupid, the boy god of love, his bow at his feet. Its string is slack, indicating that an arrow has been shot. The other figure is an allegory of Deceit, appropriately wearing a mask and a fox’s skin over his back. Juno in all her majesty is the focus of his picture, dominating the scene. Jupiter has been relegated to the ranks of the humans, guilty and vulnerable in his nakedness as he leans away from her. Just his tender hand caressing the cow’s soft curls and the closeness of Cupid suggest that this was a love story.

Stories of the misdeeds of the Greek and Roman gods were popular subjects for paintings in seventeenth-century Holland, as they were all over Europe. Lastman had been to Rome and seen the innovative paintings of Caravaggio and his followers. He takes on their use of chiaroscuro – dramatic use of light and shadow – and expressive movement to tell this moment of discovery in Io’s story, taken from Ovid’s Metamorphoses.

Lastman reveals his skill in the painting of the human body, but perhaps most of all shows his enjoyment of the contrast in textures in the picture. The purple cloth shimmers in contrast with the matte blue fabric of Jupiter’s cloak. Cupid’s strong, youthful body almost glows beside the rougher, tougher flesh of Jupiter and Deceit. Io’s curls would give quite a different sensation to the touch of Jupiter’s coarse beard or Juno’s flyaway lock of hair, and the peacocks‘ stiff feathers lack the delicacy of Cupid’s wings.

The usual purple and green eye patterns are missing from the tail feathers of these two peacocks. It’s not a mistake; it’s part of the story. Juno pretended not to know that the cow was Io in disguise and asked Jupiter to give her the animal. She put her under the guard of Argos, a giant with a hundred eyes. Jupiter had him killed and Juno placed the eyes on all peacock tails. Io, meanwhile, wandered the earth. In her travels she swam the strait between Europe and Asia that became known as the Bosporus, which translated means ’ox-ford'. Eventually she reached Egypt where Jupiter persuaded his wife to allow him to change her back, and Io gave birth to their son.

Lastman returned from Rome to live in Amsterdam where the young Rembrandt became his student for six months and the seeds were sown of Rembrandt’s style: narrative paintings that use the techniques of chiaroscuro and dramatic expression that Lastman brought with him.