A werewolf (from Old English: wer, "man"), man-wolf, or lycanthrope (Greek: λυκάνθρωπος, lykánthropos: λύκος, lykos, "wolf", and ἄνθρωπος, anthrōpos, "human") is a mythological or folkloric human with the ability to shapeshift into a wolf or a therianthropic hybrid wolf-like creature, either purposely or after being placed under a curse or affliction (e.g. via a bite or scratch from another werewolf). Early sources for belief in lycanthropy are Petronius (27–66) and Gervase of Tilbury (1150–1228).