The search for the historical figure behind what is arguably the most famous cycle of legends ever has been unrelenting over the centuries. Here, two noted Arthurian experts argue that the man whose story started the Arthurian myth was a soldier named Lucius Artorius Castus who lived at the end of the second century AD. Castus's extraordinary career took him from one end of the Roman Empire to the other, bringing him into contact with tribespeople...