A half-length male nude, carved in the early sixteenth century from wood and painted to resemble flesh marked with blood, is an arresting presence in the Castello Sforzesco in Milan (Fig. 1.1). The arms of the figure are bound behind its back and drips of red paint on the shoulders evoke the crown of thorns. That crown is absent, however, because the head of Christ has been replaced by a demonic one. Its monstrous fleshy visage, harrowing expression, and gaping orifices are accentuated with calligraphic lines. Its ears are part human, part creature, its eyes are simultaneously penetrating and vacant, and its serrated teeth flash from a gaping jaw. Hinged like a human mandible, the mouth opens to eject a flame-red tongue. Animated by a metal crank at its base, the devil spews smoke, even flames, emitting a yowling cry as its glass eyes roll wildly.

The automaton manifests transformative effects ascribed by early moderns to a fallen, or evil, soul. Startling viewers, it conjures bodily reactions from onlookers similar to those performed by the sculpture – externalising expressions of interior movements of the mind and the passions. These effects are emphasised in the description, in Chapter 7 of the guidebook to the museum, that was published in 1666: ‘De i moti quasi perpetui’ (On the motions, as if perpetual):