Knight is one of the ranks assigned to the spirits catalogued in the grimoire tradition, and above all in the Ars Goetia, the first book of the seventeenth-century Lesser Key of Solomon (Lemegeton). It denotes the lowest of the ranks named, held in the Goetia by a single spirit, Furcas.
The ranks of the spirits
The Goetia lists seventy-two spirits and gives most of them a rank, King, Prince, Duke, Marquis, Earl or Count, President, or Knight, borrowed from the feudal and civil offices of the human world, together with the number of legions each is said to command. The scheme draws on earlier sources, notably the Pseudomonarchia Daemonum printed by Johann Weyer in 1577.
The rank is described here as a feature of these documented magical texts, studied as historical literature; the spirits so ranked are not reified.
Knight differs from the catalogue's other ranks in one further way: in the medieval and early modern European system the word described, it was not, strictly, a title of the peerage at all but a personal military rank and honour, conferred individually rather than inherited, standing below Duke, Marquis, Earl and even Baron in most formal precedence. Furcas, the sole spirit given this rank in the Goetia, is described in the text as an old man with a long beard riding a pale horse and carrying a sharp weapon, credited with teaching logic, rhetoric, astrology and related sciences, a scholarly rather than martial portrait despite the military title attached to him.
Sources Lemegeton Clavicula Salomonis (The Lesser Key of Solomon)Anonymous (unidentified compiler) with Encyclopaedia Britannica (online academic reference)Encyclopaedia Britannica editors