Hardly an authoritative source, Annemieke.

Check out your own country's 'De Zevensprong' which is the Dutch version. It is well-known in France, Germany and Holland as well as English-speaking countries. The Opies (The Singing Game) trace British versions at least as far back as 1745, and conjecture it is much older. In their lengthy authoritative article p391-8 they make no mention of werewolves.