According to Christian demonology the number of demons is high. It can be deduced from the fact that the Bible mentions fallen angels, and not only one. More has growth the number of demons when Christian theology said that all Pagan deities were demons.

In early times of Christianity it was accepted an unknown number of demons, but later, during the late Middle Age, some demonologists tried to evaluate this number.

Some scholars did not accept a unique number of demons. Gregory of Nyssa, in the 4th century, supported the idea that demons procreated with other demons and with women, believing in the existence of male and female demons.

Other scholars supported the idea that the number of demons was unique and they could not procreate.

As it had been said by Christian theology that there was 400 millions of angels, Alfonso de Spina calculated that about one third of them were demons, and in 1467 he asserted that the number of demons was 133,316,666 demons. This idea of one third of the angels turned into demons seems to be due to an exegesis of the Book of Revelation 12:3-9.

Johann Weyer, in his Pseudomonarchia Daemonum (1583) after a complicated system of hierarchies an calculations, estimated the number of demons in 44,435,622, divided in 666 legions, each legion composed by 6,666 demons, and all of them ruled by 66 hellish dukes, princes, kings, etc. He forgot to add the rulers of these rulers to the total, but not to mention them in his book. Besides, the number of legions mentioned by Weyer varies in different editions of his book.

The Lesser Key of Solomon (17th century) copied the division in legions from Pseudomonarchia Daemonum but added more demons, and so more legions; anyhow, its anonymous author did not calculated the number of demons cited in this work. According to the editions of this book the number varies too.

It is suggestive that both Spina and Weyer used the 666 and other numbers composed by more than one 6 to calculate the number of demons (133,316,666 demons, 666 legions, 6,666 demons in each legion, 66 rulers).

See also