Published in English by S. L. MacGregor Mathers in 1889, The Key of Solomon the King, or Clavicula Salomonis, belongs to a long and varied European manuscript tradition of ceremonial magic. Although traditionally attributed to the biblical King Solomon, the work is not considered to have been written by him. The surviving Key of Solomon developed through much later manuscript traditions and circulated in differing Latin, Italian and French forms.

Mathers produced his edition by comparing manuscripts then held in the British Museum. His sources included texts in Latin, Italian and French, and his edition combines material from several witnesses rather than translating one single manuscript. The resulting work is arranged principally into two books and presents a structured system of ritual preparation and magical operations.

The first book discusses planetary days and hours, the construction of the magical circle, prayers, confessions and conjurations, followed by operations concerned with such purposes as recovering stolen property, invisibility, obtaining favour and seeking hidden treasure. It also introduces the pentacles associated with the planets. The second book concentrates on ritual preparation: fasting and purification, ceremonial clothing, incense, water, fire, magical instruments and the preparation and consecration of objects required for the operations.

Religious language runs throughout the text. Divine names, Psalms, angels and prayers appear alongside astrological correspondences, pentacles and ritual instructions, illustrating the close relationship between Christian, Jewish and magical elements within the European grimoire tradition as represented by Mathers’s sources.

The Key of Solomon is historically significant not as an authentic work of the biblical Solomon, but as one of the major textual traditions of European ritual magic. Mathers’s edition helped make material previously preserved largely in manuscripts accessible to English-speaking readers and became an influential reference point for later interest in ceremonial magic.