An American tourist travelling in Limerick came across a little antique shop in which he was lucky enough to pick up, for a mere $150, the skull of Saint Patrick. Included in the price was a certificate of the skull's authenticity, signed by Saint Patrick himself. Ten years later the tourist returned to Ireland and asked the antique shop owner if he had any more bargains. "I've got the very thing for you," said the Irishman. "It's the genuine skull of Saint Patrick". "You swindler!" shouted the American. "You sold me that ten years ago," and, producing the skull, added, "Look, they're not even the same size!" "You have it all wrong," said the Irishman. "This is the skull of Saint Patrick when he was a lad."