What is the first appearance of a Lich in fantasy literature? I will accepts answers pointing to myths ans sagas and such as well.
Edit: For clarity, I'm asking about Liches as defined by Wikipedia:
Often such a creature is the result of a transformation, as a powerful magician or king striving for eternal life uses spells or rituals to bind his intellect to his animated corpse and thereby achieve a form of immortality. Liches are depicted as being clearly cadaverous, their bodies desiccated or even completely skeletal. Liches are often depicted as holding power over hordes of lesser undead creatures, using them as soldiers and servants.