Legends of vampires have existed for millennia; cultures such as the Mesopotamians, Hebrews, Ancient Greeks, and Romans had tales of demonic entities and blood-drinking spirits which are considered precursors to modern vampires. Despite the occurrence of vampire-like creatures in these ancient civilizations, the folklore for the entity we know today as the vampire originates almost exclusively from early 18th-century Southeastern Europe, particularly Transylvania as verbal traditions of many ethnic groups of the region were recorded and published. In most cases, vampires are revenants of evil beings, suicide victims, or witches, but can also be created by a malevolent spirit possessing a corpse or by being bitten by a vampire itself. Belief in such legends became so rife that in some areas it caused mass hysteria and even public executions of people believed to be vampires.