The Moon in Cornelius Agrippa's De occulta philosophia
Silver, pearls, mansions and the magic square of nine: how Cornelius Agrippa described the Moon in De occulta philosophia, printed in full in 1533.
Heinrich Cornelius Agrippa of Nettesheim, born in Cologne in 1486 and died in 1535, was a physician, jurist, soldier and above all the author of the most famous compendium of magic of the Renaissance, De occulta philosophia libri tres. A first draft was already circulating in manuscript around 1510; the first book was printed in 1531 and the complete work appeared in 1533. In this vast encyclopaedia the Moon appears in a great many chapters, as a planet, as a symbol and as a channel of correspondences.
A system of correspondences
The first book, devoted to natural magic, gathers the things that tradition considered «lunar»: silver, white and iridescent stones such as selenite and pearl, animals linked to water and to night, plants that follow the rhythm of day and night or grow in damp places. Agrippa draws on Pliny the Elder, Albertus Magnus, the Picatrix and many ancient and medieval sources, arranging them in a system of sympathies and antipathies.
The underlying idea is that every earthly thing shares in the nature of a heavenly body, and that these affinities were impressed by God at the creation. The Moon, according to Agrippa, presides over moisture, growth and change, and her influence shows itself in the tides, in the cycle of waters and in the phases of plant life. These ideas repeat almost word for word ancient physics, filtered through the medieval astrological tradition and the Neoplatonism of Ficino.
The square of nine
In the second book, devoted to mathematical magic, Agrippa presents the so-called magic squares of the planets, tables of numbers arranged so that the sums of rows, columns and diagonals are always equal. To the Moon belongs the square of order nine, the largest in the series, made up of eighty-one cells: each row adds up to 369 and the total of all the numbers is 3321. Saturn receives the smallest square, of order three.
The choice of nine for the Moon follows the order of the spheres: Saturn, the most distant planet, receives three, then Jupiter four, Mars five, the Sun six, Venus seven, Mercury eight and finally the Moon, the closest to the Earth, nine. Magic squares had been known for centuries in Arabic and Indian mathematics; the square of Jupiter already appears in Albrecht Dürer's famous engraving Melencolia I, dated 1514.
Mansions, images and contradictions
The same second book contains the list of the twenty-eight lunar mansions, with their Arabic names and the properties attributed to each, and a series of astrological images inherited from the medieval tradition. Agrippa also takes up the theme of the Moon as the channel of the lower world, gathering the influences of the planets and passing them on to matter. The third book, devoted to ceremonial magic, places these elements within a broader discussion of religion and the purification of the soul.
The work had a singular fate. In 1530 Agrippa had published De incertitudine et vanitate scientiarum, in which he harshly criticised all the sciences, magic included. This contradiction, still debated by scholars, fed his legend as a restless magician, which long survived in European literature. The so-called Fourth Book of occult philosophy, attributed to him after his death, was already declared spurious by his pupil Johann Weyer.
De occulta philosophia is today an indispensable source for understanding the magical culture of the Renaissance. Its pages on the Moon show how a sixteenth-century intellectual tried to unite ancient physics, mathematics, astrology and theology in a single system, building a cosmos in which everything, from silver to the pearl and the number nine, pointed back to the pale light of the night.