One of the horrific night visitors that prey on Roman sleepers were the incubi and succubi In some cases, these two were said to be differing aspects of the same demon. But it was generally held that the incubi was male whilst the other, much more prolific and dangerous succubus, was female. The name succubus probably comes from the Latin succubare, meaning “to lie under” and it is possible that the demon was a variant of the Greek Mormo, who was sometimes considered to be both female and sexually voracious. Indeed, it was a sexually voracious appetite that characterised both the incubus and the succubus. Both demons (or various aspects of the one demon) had sexual intercourse with men and women as they slept. The succubus in particular drew the seed from sleeping men, sexually exhausting them, and might have even done so to do them harm. Although initially a terror in ancient Rome, the succubus was to assume greater attention in the early Christian period right through to the Middle Ages, when the demon was thought to plague monks in order to distract them from their holy vows. Monks often experienced erotic
dreams and nocturnal emissions, which were credited to the attentions of the succubus during the night. In his Compendium Malificarum, written some time in the 16th century, the Milanese monk and demonologist Francesco Maria Guazzo details succubi in his list of demons that torment the righteous. He states that these dreams are in fact real and the experiences of the monks, in the throes of their eroticism, were due to a completely physical manifestation of the demon whose desire was not only to break their vows of chastity but to do them actual harm. Guazzo was following the categories of demons, which had been established by the Byzantine thinker, Michael Psellus the Younger. It is thought that Psellus was born around 1018 in the city of Nicodema (now Izmit on the Gulf of Astacus) and that, as a child, he had been exposed to both Greek and Roman culture. Although more associated with the Platonist school of thought, Psellus did outline certain categories of demons, one of which was
“terrors of the night” which included beings that both extracted semen and drank blood. This would undoubtedly prove the inspiration for Guazzo many centuries later.