There were always attempts to classify demons in several categories. Christian demonology accepted that, providing several classifications of the demons.

The first classification was the same that Judaism and other religions had, involving the demons' sexual behaviour (later this simple classification became complex):

But this classification soon became insufficient, and other demonologists suggested different patterns to classify demons. In this way there were classifications based on their nature, the sin with which they tempt humans, the month in which their power was stronger, the saints that were their adversaries, etc. Here follow some examples, listed in chronological order:

It can be noted that according to every author the domain of each demon is very different, with the exception of Francesco Maria Guazzo that seem to have copied Michael Psellus with a little difference. It can also be seen that each author chooses his demons in a random form. The classification of demons by month seems to have astrological implications more than religious ones.

There were other classifications, by office, like those written in several grimoires; these are some examples:

The author of The Lesser Key of Solomon copied Pseudomonarchia Daemonum almost literally, but added demons' descriptions, their seals and details.

See also Hierarchy of the demons.