The myth of Aethelred "the Unready" is disproved and Britain's military prowess in the face of Danish invasion is repositioned. The Danish invasions in the second decade of the 11th century came after unprecedented Viking attacks stretching back 30 years. Earlier kings of Wessex had held and pushed back the tide of Danish encroachment, but faced by wave after wave of incursions from powerful Scandinavian raiders, including fierce Thorkill "the tall," wily Olaf Tryggvason, and the redoubtable Swein Forkbeard, the English forces buckled under the mounting pressure. Though losing and then regaining his kingdom through force of arms makes him one of only two English monarchs ever to do so, Aethelred II remains an enigma, slighted as the "unready." No less so his son Edmund (Ironside), whose energetic campaign against Canute in 1016 would decide England's fate. For the first time, the military history of this turbulent period of conflict reveals the true nature of England's armies and her kings.