Belfagor (Arcidiavolo)

The figure appears first in Renaissance literary sources as the protagonist of Niccolò Machiavelli’s novella Belfagor arcidiavolo, written between 1518 and 1527 and first published in collections of his works in 1549. In Machiavelli’s treatment the title names him explicitly as an 'arcidiavolo' (arch-demon). Later authors adapted the tale into dramatic and musical forms (including a comedy by Ermanno Morselli and Ottorino Respighi and Claudio Guastalla’s 1923 opera), which preserve the core premise of a high-ranking infernal being dispatched from the underworld on a temporal mission among humans.

Primary sources do not supply a single fixed monstrous form; instead the narratives emphasize Belfagor’s capacity for human disguises. In Respighi’s opera he first appears in a village, later assumes the identity of the handsome and immensely rich Ipsilonne to secure a wife, and in the epilogue adopts the guise of a vagabond. Machiavelli’s novella gives the character his arch-demonic title but the supplied summaries do not record a detailed, consistent physical description.

As presented in the literary and operatic sources, Belfagor is an infernal envoy sent from the underworld with a defined investigatory task (in Respighi’s opera: to discover whether marriage is 'truly a hell for mankind'). He employs disguise and social guile, can present himself as a wealthy noble (using money as inducement), and engineers deception to test or unsettle human characters. Narratives portray him assuming multiple social appearances (nobleman, vagabond) and leaving or vanishing from the human scene after his episodes; these are plot behaviors attested in the adaptations rather than catalogued thaumaturgic mechanics.