Before the birth of Theseus, his father had left a sword and pair of sandals under a great stone, to be claimed when the boy had grown sufficiently in strength to lift it. Castiglione (1609-64) has illustrated the moment of triumph when the hero demonstrates his prowess by recovering these tokens, while his mother looks on.The function of printmaking is to produce multiple images from a single printing matrix. Castiglione had etched this composition on a copper plate, from which he had pulled repeated impressions. But he also drew the image on an unworked plate in printing ink from which he printed a unique impression. He thereby invented monotype, the only Italian to devise a printmaking process.Fourteen of Castiglione's twenty-one monotypes are set at night. Castiglione had copied prints by Rembrandt, who by manipulating printing ink had solved the problem of areas of shadow which were difficult to reproduce in the lines of an etching. Inking a plate all over in black, and then removing the ink with the fingers, a rag, or the wooden end of a paintbrush, allowed rich areas of dark tone to be printed. With this method, a gifted draughtsman like Castiglione could rapidly conjure up the flames and smoke from a lighted torch, or the evocative shapes of monuments emerging from the gloom, in a manner impossible with established printmaking processes. Mezzotint was invented in this decade as an alternative method of printing tone.