What  influence did the invasions of the ninth century have on European  development?

What  influence did the invasions of the ninth century have on European  development? What motivated these invasions? What do you think led to  their eventual decline? 

Many  groups like the Vikings and other pirate groups realized they could  raid towns and monasteries to plunder their riches with virtually no  resistance. It became more common and had the effect of creating the  feudal system. This system was decentralized from the fall of the  Carolingian Empire. Farmers pledged their lands to local lords who in  turn pledged to protect them from invasions. This in turn led to the  creation of additional castles and knights. Castles became refuge for  citizens fleeing invading groups while knights were tasked with  defending

The  invasions subsided over time as defenses increased around Europe.  Christian kingdoms were spreading across Europe creating a more unified  front to invaders. There was a concerted effort to convert all the  Scandinavian nations with Christian kings by 1066 CE.

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