Viking expansion: Viking raiders, possibly led by the legendary Ragnar Lodbrok, plundered and occupied Paris, holding the city for a large ransom. Siege of Paris (845): The siege of Paris of 845 was the culmination of a Viking invasion of West Francia. The Viking forces were led by a Norse chieftain named "Reginherus", or Ragnar, who has been tentatively identified with the legendary saga character Ragnar Lodbrok. Reginherus's fleet of 120 Viking ships, carrying thousands of warriors, entered the Seine in March and sailed up the river. March 29, 845. Wiki link