The Vikings first began to raid what would become Normandy in the 790s and had established several permanent coastal settlements by the beginning of the 10th century. At this time, Rollo was a Viking chieftain based in Rouen, who had conducted raids on both Paris and Rouen. In a pragmatic move, the French king, Charles the Simple, recognized Rollo’s title to the lands between the River Epte and the sea in 911. In return, Rollo converted to Christianity and became the Frankish ruler’s shield against further Viking incursions. The weakness of the French monarchy was further exploited to acquire Bessin in 924, and Cotentin in 933. In the second half of the 11th century, Richard the Fearless turned Normandy into a strong, well administered feudal state. William the Conqueror would deploy this strength to add northwestern France in 1050, and later, England.
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