EVOCATION. – From Latin *evocatio*: a magical rite by means of which one summons either a soul from the underworld or a deity from its abode. Evocation almost always has a divinatory purpose (necromancy), and it is found both among the ancient peoples of advanced culture and among contemporary primitive peoples.
In the classical Greco-Roman world, in addition to the account by Lucian, who mentions Chaldean magicians as masters of astrology as experts in this art, several evocators are known (one may cite Tiresias and his daughter Manto, Medea, and Canidia) and famous cases of evocation: such as the one connected with Pompey at the battle of Pharsalus, in which a sorceress, Eritho, evoked a dead man to predict the outcome of the battle, and the evocation of Queen Juno by Camillus during the battle of Veii (Livy, V, 21).
The evocatory rite essentially belongs to that particular form of magic which recognizes a magical efficacy in certain gestures and words. Since, through evocation, one can deprive an enemy of the aid of his deities, it is evident that an aura of mystery surrounds the evocatory magical formulas, which are therefore known only to a select personnel, delegated to this type of practice, such as, in Rome, the college of Pontiffs (cf. Macrobius, *Sat.*, III, 9).