<Li> Leuven (891) </Li> <Li> Trans (939) </Li> <P> The Siege of Paris and the Sack of Paris of 845 was the culmination of a Viking invasion of the kingdom of the West Franks . The Viking forces were led by a Norse chieftain named "Reginherus", or Ragnar, who traditionally has been identified with the legendary saga character Ragnar Lodbrok . Ragnar's fleet of 120 Viking ships, carrying thousands of men, entered the Seine in March and proceeded to sail up the river . The West Frankish king Charles the Bald assembled a smaller army in response, but as the Vikings defeated one division, comprising half of the army, the remaining forces retreated . The Vikings reached Paris at the end of the month, during Easter . After plundering and occupying the city, the Vikings withdrew when they had been paid a ransom of 7,000 French livres (2,570 kilograms (83,000 ozt)) of silver and gold from Charles the Bald . </P> <P> The Frankish Empire was first attacked by Viking raiders in 799 (ten years after the earliest known Viking attack at Portland, Dorset in England), which led Charlemagne to create a defence system along the northern coast in 810 . The defence system successfully repulsed a Viking attack at the mouth of the Seine in 820 (after Charlemagne's death), but failed to hold against renewed attacks of Danish Vikings in Frisia and Dorestad in 834 . The attacks in 820 and 834 were unrelated and relatively minor, and more systematic raiding did not begin until the mid-830s, with the activity alternating between the two sides of the English Channel . Viking raids were often part of struggles among Scandinavian nobility for power and status, and like other nations adjacent to the Franks, the Danes were well - informed about the political situation in Francia; in the 830s and early 840s they took advantage of the Frankish civil wars . Major raids took place in Antwerp and Noirmoutier in 836, in Rouen (on the Seine) in 841, and in Quentovic and Nantes in 842 . </P>

What year did the vikings invade paris france