In July 2009 an amateur metal-detecting enthusiast made an astonishing find: 1500 pieces of bejeweled gold and silver almost 1500 years old, buried, lost, then forgotten. The treasure trove promises to shed unprecedented light on the most mysterious period of British history--the so-called "Dark Ages"--when the Saxons, Anglos, Celts, Picts, Jutes, and Vikings battled for control of the British Isles and a "mish mash of peoples evolved into a homogenous...