Demonology in the Western tradition is above all a literature of lists, and the lists have a traceable history that is more interesting than the entries.
The catalogue that stands behind most later ones was printed as an appendix to Johann Weyer's work on the deceptions of demons in the sixteenth century. Weyer's own purpose was the opposite of what his list has since been used for: he was arguing that the women being executed as witches were deluded or ill rather than guilty, and he set out the hierarchy of spirits in part to show how absurd the whole apparatus was. His catalogue was then copied, extended and eventually reissued as an instrument for summoning.
The names themselves come from several directions. A number are recognisably deities of neighbouring or earlier religions, demoted rather than invented, with their titles worn down by transmission through Greek, Latin and Hebrew. Others are corruptions that entered as copying errors and acquired biographies afterwards, so that a scribal slip becomes a duke of hell with thirty legions.
The offices attached to each spirit follow the anxieties of the people compiling them: finding treasure, teaching languages, revealing the future, procuring favour.
Read as a record of what demons are, the lists are worthless. Read as a record of what their compilers wanted, feared and had inherited, they are among the more revealing documents in this atlas.