Although the origins of werewolves are traditionally attributed to the Middle Ages, tales of humans transforming into wolves have been documented from as early as 440 BC.
Greek mythology contains the story of a king named Lycaon, who was transformed into a wolf after serving a bowl of human flesh to Zeus; another version of the story tells of Lycaon’s transformation into a wolf as punishment for sacrificing a child to Zeus. This tale resulted in the belief that from that point on, one man was turned into a wolf at the annual sacrifice to Zeus, but would be able to regain his human form after abstaining from human flesh for ten years.
In one of his writings, a Roman scholar named Pliny the Elder quoted the Greek author Euanthes, who told the story of a man who was selected by lot to swim across a lake, where he hung his clothing on a tree, and – upon swimming across the lake – was transformed into a wolf for nine years. The man was only able to swim back across the lake and regain human form if he did not attack any humans during those nine years.
The Greek historian Herodotus, in his work Histories, discussed a tribe to the north-east of Scythia called the Neuri, who were annually transformed into wolves for several days.
The Latin poet Virgil took a different approach, and in one of his writings described a sorcerer who was able to ingest a certain combination of lethal herbs that would turn himself into a werewolf; in the year 60 A.D., the Roman playwright Gaius Petronius composed his novel Satyricon, in which a character recites a story about a man who transforms into a wolf during a full moon.