Liber Iuratus Honorii: the Sworn Book of Honorius of Thebes

The prologue of the Liber Iuratus Honorii tells a dramatic story. The pope and cardinals, incited by the devil, had supposedly resolved to destroy the magicians and their books; the masters of the art then gathered in a great council and chose Honorius, son of Euclid and master of Thebes, to collect their knowledge in a single volume. Hence the name «Sworn Book»: whoever received it had to swear to guard it and pass it on only to persons deemed worthy.

Dating and manuscripts

The text has been placed between the mid-thirteenth century and the first decades of the fourteenth, and the exact date of composition is still debated. Some scholars have related the prologue to the climate of the early fourteenth century, when Pope John XXII, with the bull Super illius specula issued around 1326, equated the practice of magic with heresy. The tale of persecution in any case reflects an age of growing repression.

The principal manuscripts are held at the British Library: Sloane 3854 and 313, in Latin, and Royal 17 A XLII, a sixteenth-century English translation. The Swedish scholar Gösta Hedegård published a critical edition of the Latin text in 2002, which made a systematic study of the work possible. Partial versions and reworkings also exist in other European manuscripts.

The vision of God

The highest aim declared by the Sworn Book is surprising: to attain in this life the beatific vision of God, which theology reserved for the blessed after death. The text devotes to this goal a long course of prayers, confessions, fasts and invocations of divine names, presented as a path of purification. Only afterwards does it turn to subjects more usual in ritual magic, such as knowledge of the spirits of the planets and of the air.

This combination of mystical ambition and magical technique makes the Liber Iuratus a valuable document of late medieval religious culture. The text takes over large sections of prayers from the Ars Notoria and shows links with other works of Solomonic magic, belonging to a network of texts that circulated among educated clerics able to read Latin and to handle the language of the liturgy.

Honorius and his namesakes

Honorius of Thebes should not be confused with Pope Honorius III, to whom another text is attributed, the Grimoire of Pope Honorius, which appeared in print much later, between the seventeenth and eighteenth centuries, with fictitious dates. The two books have no connection in content, but the similarity of name has caused confusion among readers and bibliographers for centuries.

Honorius's name is also attached to a magical alphabet, the so-called Theban alphabet, which appears in print in Trithemius's Polygraphia of 1518 and then in Agrippa's De occulta philosophia, where it is attributed precisely to Honorius of Thebes. This attribution, too, shows the strength of the figure as an authority of medieval magic, well beyond the bounds of his book.

The Sworn Book is now regarded as one of the key texts for understanding medieval ritual magic. Its history tells of an age in which the Church repressed magic as heresy while, on the other hand, some clerics sought in prayers and divine names an extraordinary path to God, defying the limits that theology had set.