Conjuror

Evocation is the act of calling upon or summoning a spirit, demon, god or other supernatural agent, in the Western mystery tradition. Comparable practices exist in many religions and magical traditions and may employ the use of mind-altering substances with and without uttered word formulas.

The Latin word evocatio was the "calling forth" or "summoning away" of a city's tutelary deity. The ritual was conducted in a military setting either as a threat during a siege or as a result of surrender, and aimed at diverting the god's favor from the opposing city to the Roman side, customarily with a promise of a better-endowed cult or a more lavish temple.Evocatio was thus a kind of ritual dodge to mitigate looting of sacred objects or images from shrines that would otherwise be sacrilegious or impious.

The calling forth of spirits was a relatively common practice in Neoplatonism, theurgy and other esoteric systems of antiquity. In contemporary western esotericism, the magic of the grimoires is frequently seen as the classical example of this idea. Manuals such as the Greater Key of Solomon the King, The Lesser Key of Solomon (or Lemegeton), the Sacred Magic of Abramelin the Mage and many others provided instructions that combined intense devotion to the divine with the summoning of a personal cadre of spiritual advisers and familiars.

The grimoires provided a variety of methods of evocation. The spirits are, in many cases, commanded in the name of God - most commonly using cabalistic and Hellenic 'barbarous names' added together to form long litanies. The magician used wands, staves, incense and fire, daggers and complex diagrams drawn on parchment or upon the ground. In Enochian magic, spirits are evoked into a crystal ball or mirror, in which a human volunteer (a 'seer') is expected to be able to see the spirit and hear its voice, passing the words on to the evoker. Sometimes such a seer might be an actual medium, speaking as the spirit, not just for it. In other cases the spirit might be 'housed' in a symbolic image, or conjured into a diagram from which it cannot escape without the magician's permission.

...
Wikipedia