When I’m at an event wearing all my medieval clothing I could, to all intents and purposes, be somebody from the ninth century. Okay, if you did isotopic analysis of the metal in my knives and the fibers in my clothes you’d find modern stuff, like pieces of plastic and dirt and modern radioactive isotopes from nuclear testing done during the fifties, caught up in them. But just by a surface physical examination I could be a ninth-century Viking — down to my teeth and dental work.