 During the ninth century, these warrior-bands regularly laid waste to the lands of the Frisians, sailed up rivers like the Seine, Loire, and Rhine, where they caused great devastation in the country, and plundered Carolingian monasteries and episcopal cities.After 841, only in the years 874 and 875 are there no references to Viking activity.There is much to read in the annals, and the narrative sheds also some light on the many incidents that form the scenario in which Scandinavians came to more formal, i.e.