Viking Ships Sail Up the Seine and Plunder Paris

In March 845, a fleet of 120 Viking ships, a figure given by the Annals of Saint-Bertin, carrying, by some modern estimates, more than 5,000 warriors, entered the mouth of the Seine and moved inland toward the heart of West Francia. The force was led by a Norse chieftain named Reginherus, or Ragnar, whom historians have tentatively connected with the legendary saga figure Ragnar Lodbrok. As the flotilla advanced along the river corridor, it plundered settlements along the banks, posing a direct military challenge to the authority of King Charles the Bald.

Decades earlier, the Frankish ruler Charlemagne had organized coastal defenses after northern raiders began probing the empire at the close of the eighth century. Those early protective networks initially repulsed a minor incursion on the Seine in 820. However, political fractures among the Carolingian ruling elite during the 830s and 840s created vulnerable openings. Scandinavian raiders took advantage of these divisions to mount increasingly ambitious assaults against trading centers such as Antwerp, Noirmoutier, and Nantes.