May 13, 1935 –

The classic Universal Pictures horror film, Werewolf of London, directed by Stuart Walker and starring Henry Hull, Warner Oland, Valerie Hobson, Lester Matthews, and Spring Byington, opened on this date.
This film made up much of its werewolf mythology out of whole cloth. The ideas that being bitten by a werewolf makes one a werewolf, that a werewolf changes under the full moon, and that werewolves were wolf/man hybrids were completely made up.
