Unlike vampires, you can actually trace the myth of the werewolf back to the Grecian myth itself. There is the story of the Arcadian King Lyacon who tried to test Zeus by serving him meat from his own dead son, to see if the all-powerful Zeus was as clever as the legends told. As punishment, Zeus turned him into a wolf and killed his sons. Beyond this, there are many folklore tales, particularly in Eastern Europe, about men and women who can shapeshift into beasts, including the wolf. In medieval periods the werewolf was actually quite benign, being more of a victim of sorcery and evil magic, succumbing to the king as a knight's errand. In terms of literature, the earliest example of a wolf-to-man transformation is in the Epic of Gilgamesh from the second millennium BC which is arguably one of the oldest texts out there. Ishtar, the goddess of fertility, was in love with Gilgamesh, yet, when he rejected her advances because of her history with previous suitors. Gilgamesh recounts how one suitor was turned into a wolf by Ishtar because she grew bored of his advances and worship of her, leading to his own death as he was a shepherd and his own dogs tore him to shreds. While neither necessarily talk about werewolves directly but show how the werewolf curse is something often given by gods in anger, rather than something used for power. It’s easy to see how countless stories came from these ancient descriptions of werewolf transformations.