> The Vikings started to raid the Seine valley during the middle of the 9th century. As early as 841, a Viking fleet appeared at the mouth of the Seine, the principal route by which they entered the kingdom.[7] After attacking and destroying monasteries, including one at Jumièges, they took advantage of the power vacuum created by the disintegration of Charlemagne's empire to take northern France.
The fiefdom of Normandy was created for the Viking leader Hrólfr Ragnvaldsson, or Rollo (also known as Robert of Normandy). Rollo had besieged Paris but in 911 entered vassalage to the king of the…