The Sworn Book of Honorius

The Sworn Book of Honorius, or Liber Juratus (also Liber Sacer/Sacratus/Consecratus, often confused with the Grimoire of Pope Honorius), is a medieval grimoire purportedly written by Honorius of Thebes. The book is one of the oldest existing medieval grimoires as well as one of the most influential.

Its date of composition is uncertain, but it is possibly mentioned as Liber Sacer in the 13th century, apparently asserting a high medieval date. The first certain historical record is the 1347 trial record of Olivier Pepin from Mende France.Johannes Hartlieb (1456) mentions it as one of the books used in necromancy. The oldest preserved manuscript dates to the 14th century, Sloane MS 3854 (fol 117-144). Sloane MS 313, dating to the late 14th or early 15th century, was once in the possession of John Dee.

It is supposedly the product of a conference of magicians who decided to condense all their knowledge into one volume. In 93 chapters, it covers a large variety of topics, from how to save one's soul from purgatory to the catching of thieves or finding of treasures. It has many instructions on how to conjure and command demons, to work other magical operations, and knowledge of what lies in Heaven among other highly sought information. Like many grimoires, it has lengthy dissertations for proper operation and seals to be used.

The book can be classified as a "Solomonic Grimoire" due to its heavy use of angelic powers and seals like those found in The Key of Solomon, and its own claim to "lay out the works of Solomon".

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