In the Middle Ages, it was commonly believed that the souls of the dead could return to earth and haunt the living.
The belief in Revenants (someone who has returned from the dead) are well documented by contemporary European writers of the time. According to the Encyclopedia of Things that Never Were, particularly in France during the Middle Ages, the revenant rises from the dead usually to avenge some crime committed against the entity, most likely a murder.
The revenant usually took on the form of an emaciated corpse or skeletal human figure, and wandered around graveyards at night.
The Draugr of medieval Norse mythology were also believed to be the corpses of warriors returned from the dead to attack the living.
The zombie appears in several other cultures worldwide, including China, Japan, the Pacific, India, and the Native Americans.
The Epic of Gilgamesh of ancient Sumer includes a mention of zombies. Ishtar, in the fury of vengeance says:
Father give me the Bull of Heaven,
So he can kill Gilgamesh in his dwelling.
If you do not give me the Bull of Heaven,
I will knock down the Gates of the Netherworld,
I will smash the doorposts, and leave the doors flat down,
and will let the dead go up to eat the living!
And the dead will outnumber the living!
Origins of zombies