It was a foggy June day in the year 793 A.D. when several longboats with dragon’s-head prows silently appeared out of the fog bound for the Lindisfarne monastery off the Northumbria coast. Howling like wolves, the Vikings methodically set about the business of slaughter. Some monks were killed midway through their prayers. Others were felled trying to defend their hand-lettered vellum books. Those who failed to die quickly suffered “the blood eagle,” a terminal torture in which a man’s lungs were ripped from his chest and allowed to flap like crimson wings until the screams subsided. And then, just as quickly as they had come, the Vikings disappeared into the cold gray mist of the North Sea, taking with them golden chalices, silk tapestries and intricately carved triptychs while leaving behind a legacy of fear. For the next 300 years, nobles and clergy alike ended their nightly prayers with the whispered supplication: A furore Normannorum libra nos, Domine – “From the fury of the Northmen deliver us, Oh Lord.”