The ancient grimoires (textbooks of magic) engaged in long and complicated descriptions of the spirit entities one could conjure with the help of magical formulae, and to which of the planets they were aligned and what powers were attributed to them from the planet. For example, The Fourth Book of Cornelius Agrippa, an occult document of dubious origin has this to say about the forms of spirits in their manifestations:

The Spirits of Saturn appear tall and lean with an angry countenance, having four faces, of which one is in the usual position, another at the back of the head, and two, with beaks, on either side. They also have a face on each knee, of a shining black color. Their motion is like that of the wind, and it is accompanied with a kind of earthquake. Their sign is white earth. Their forms are a bearded king riding on a dragon; an old bearded man; an old woman leaning on a staff; a boy; a dragon; an owl; a black garment; a hook or sickle; a juniper tree. The Spirits of Jupiter appear with a sanguine and choleric body; they are of middle stature; their motion is "horrible and fearful," but they are mild of countenance and gentle in speech. Their motion is that of flashing lightnings, and withal thunderous; their sign is the apparition of men about the circle who seem to be devoured by lions. Their particular forms are a king with drawn sword riding on a lion; a mitred personage in a long vestment; a maid crowned with laurel and adorned by flowers; a bull; a stag; a peacock; an azure garment; a sword; a box tree.

The Spirits of Mars have a tall body and choleric, a filthy countenance, brown, swarthy or red in color; they have horns like the hart, claws like a griffin and they bellow like wild bulls. They have the motion of burning fire, and their sign is thunder and lightning about the circle. Their particular forms are an armed king riding on a wolf; an armed man; a woman holding a buckler on her thigh; a she-goat; a horse; a stag; a red garment; wool.

The Spirits of the Sun appear large of body and limb, sanguine, gross, and of a gold color tinctured with blood. Their motion is that of lightning; their sign is to produce sweat in the operator. Their particular forms are a sceptred king riding on a lion; a crowned king; a queen with a sceptre; a bird; a lion; a cock; a golden garment; a sceptre; tailed.

The Spirits of Venus have a body of medium height and a pleasant visage, of which the upper part is golden and the lower white or green. Their motion is like that of a brilliant star. Their sign is the semblance of maids sporting about the circle and luring the Magician to join them. Their particular forms are a sceptred king riding on a camel; a naked maid; a she-goat; a camel; a dove; a white or green garment; the herb savine.

The Spirits of Mercury appear commonly with a body of middle stature, cold, liquid, moist. They are withal fair, affable in speech, of human shape and like unto armed knights. Their motion is that of silver colored clouds. Their sign is to cause horror and fear in the operator. Their special shapes are a king riding on a bear; a comely youth; a woman holding a distaff; a dog; a she-bear; a magpie; a garment of many changing colors; a rod; and a little staff.

The Spirits of the Moon have a large, soft, phlegmatic body, even as a dark cloud in color. Their countenance is swollen, their head bald, their eyes are red and rheumy, their teeth like those of a wild boar. Their motion is like that of a great tempest sweeping the sea. Their sign is a heavy shower of rain about the circle. Their particular shapes are a king like an archer riding on a doe; a little boy; a huntress with bow and arrows; a cow; a small doe; a goose; a green or silver-colored garment; an arrow; a many-footed creature.

Either the ancient Magi had a wild imagination, or they were witness to some truly bizarre manifestations of supernatural phenomenon. Whatever the truth about these ancient teachings, the belief that such manifestations are possible through the application of magical rites and ceremonies has become so deeply rooted in the occult psyche that it has been endorsed by occultists through the passing of time as being in conformity with occult and cosmic laws.