The term "demons" was not always understood to have the absolutely negative connotation that it does today. Homer used the terms "demons" and "gods" more or less interchangeably. Another opinion was that demons were intermediaries between men and gods, and that demons had once been men. Plutarch speaks of "human souls as commencing, first heroes, then demons, and afterward as advancing to a more sublime degree." Philo of Byblus seems to draw on this same tradition when he states that, "The most ancient of the barbarians, especially the Phoenicians and Egyptians, from whom other people derived this custom, accounted those the greatest gods who had found out things most necessary and useful in life -- and had been benefactors to mankind."
Our current use of the term "demon" is to denote a malignant spirit, and comes to us primarily form New Testament writers. However, there is still uncertainty as to whether or not demons are considered to be distinct and separate from the Devil and his fallen angels.
Demon possession - that is, a human who has become inhabited or "taken over" by a demon and who cannot, consequently, exercise his own will - is noted in the New Testament, specifically in Mark, Chapter 5, ver. 12. Josephus also mentions a method of exorcism prescribed by Solomon, which had "prevailed or succeeded greatly among them down to the present time." Unfortunately, Josephus does not describe the method used.
There is little doubt that most of what was described in older times as "demon possession" would today be diagnosed as some sort of mental illness, and treated accordingly. Nevertheless, a few cases of possession do seem to crop up from time to time, and the Roman Catholic Church does continue (sparingly) to perform exorcisms.
Periods of Increased Demon Activity
Some historians of times past believed that there were cycles during which demonic activity increased, and used this theory to explain various occurrences, much in the same way as today's economic historians might explain historical events in terms of trade, productivity and other factors. These older historians saw a rise in demonic activity accompanying such occurrences as the destruction of Jerusalem, the fall of Rome and the French Revolution, and would in all likelihood also have viewed the demonic theory at work in relation to the rise of Nazism and World War II.
Ancients also had a sort of faith in the prophetic words spoken by those whom they believed to be possessed by demons, and this was sometimes a component of ancient oracles. In connection with this, it is worth pointing out that a respected modern-day professor of psychology once witnessed a friend, who was suffering from paranoid schizophrenia make a specific and surprising prophecy that turned out to be perfectly accurate. The professor had no explanation for this event. although one is tempted to hypothesize that there is a link between altered mental states and psychic ability. Some also associate the ouija board with demoniacal prophesy, and those who have seen Linda Blair in The Exorcist will recall that this was how her character's problems began.
Species of Demons, as Described by Alphonse de Spina (1467)
Fates, who alter destiny
Poltergeists, who cause mischief
Incubi and Succubi, who stimulate lust and perversion
Marching Hordes, who bring about war
Familiars, who assist witches
Nightmares, who disturb sleep through bad dreams
Demons formed from Human Semen
Demons who Assail the Saintly
Demons who Instigate Witchcraft
Correspondence of Demons to the Seven Deadly Sins
(According to Peter Binsfield, a Jesuit, 1589)
BelphegorVanity and Sloth
List of Demons
Acham - the demon of Thursday.
Alrinach - demon of shipwrecks....