A monotype of the Virgin cradling the Christ Child upon a heap of straw in the manger. Two adoring angels kneel close by on the left, and rays of light beam through the clouds above.

Castiglione seems to have invented the technique of monotype, a hybrid of drawing and printmaking. He explored both basic methods, the 'positive' in which the artist works up the image directly on a metal plate with sticky printer’s ink, and the 'negative' in which the plate is coated in ink and the light tones of the image are scraped away. Only 25 or so of Castiglione’s monotypes are known, unique in the seventeenth century; the technique then lay dormant until William Blake independently hit upon the same process, but it was not until the late nineteenth century that artists such as Degas and Gauguin fully exploited its potential.

The 1650s saw Castiglione experiment again with the elongated forms of late Mannerism. But now the results appear tortured rather than elegant, as seen best in his monotypes of the period. Here he dredged through the thick ink on the plate with a blunt stick to carve out stark contrasts of light and dark, creating one of the most striking works of his career and indeed of the entire seventeenth century.