Attempts to find the person (if any) behind the legend of King Arthur have been going on for a long time. By the 1980s, the search was more or less abandoned, having reached a dead-end. This work presents an investigation that broke the deadlock. Arthur emerged from it with a firmer status in history. He was also more interesting more like his legend than once appeared likely. It became possible to see better why he became the kind of figure he did. The delay in running him to earth was due to the nature of the problem he posed. Medieval authors who gave him his literary grandeur fitted him into what they claimed was Britain's history several centuries later. Not much of that history can stand up in the light of present day knowledge it is mostly legend. So historians who looked for Arthur swept the medieval matter aside and searched for him in the scanty older records. But the search was inconclusive. A convincing answer called for a different approach. This books shows that the Arthurian legend itself needs to be taken seriously and sifted for clues. If we line up the legend side by side with the facts as we know them today, the problem of Arthur's identity can be solved.