The seafaring Norse people of Scandinavia who, for nearly three centuries, burst out of the north in their superb longships to raid monasteries, found cities, settle Iceland and Greenland, reach North America, carve out states from Russia to Normandy, and trade in slaves and silver from Baghdad to Newfoundland — far more than the horned barbarians of legend, and far harder to romanticize than the modern myth allows.
The horned helmet is a lie. There is no evidence that Viking-Age warriors wore horned helmets; the image belongs to nineteenth-century romantic art and stage costume, including Wagnerian opera, and it stuck so hard that it now stands in for the whole people. Strip it away and you do not find gentle traders, either. You find something more unsettling than the cartoon: men who could carve fine art, recite long poems, and settle disputes by law, and who also sacked monasteries, sold captured people in large numbers, and made captured people one of the central commodities of their economy. The Norse were raiders, explorers, and slavers at once. The hardest thing about them is that all of it is true together.