Although, Viking raids were far from being a rare occurrence as the Frankish realms had to contend with such sudden incursions for decades, this one would prove to have everlasting consequences on European history.

Following Rollo's defeat, the King of the West Franks, Charles the Simple, granted him a territory in the northern lands of his kingdom in exchange of an oath of fealty and his religious conversion.

[4] Rollo and his followers, who likely had been conducting a raiding campaign in north central West Francia launched the siege of Chartres in spring 911 (either April or May).

But the two valleys leading off from the Eure eventually reached the plateau at the point where the Place des Épars in Chartres is located today.

The Norsemen had begun shooting arrows at the ecclesiastical group as soon as it appeared on the ramparts; but soon they fell blinded, and their leaders had no thought but to flee.

Then, the besieged troops, exiting through several gates, caught the Norsemen, who were struggling to cope with Robert's horsemen, on the back foot.

The clergy, well inspired after the blow dealt to Rollo, had judged the moment favorable to enter into peace negotiations, which led to the famous Treaty of Saint-Clair-sur-Epte.

[22] The contemporary sources present, on the whole, serious difficulties, but it remains certain that a link exists between Robert's battle with Rollo and the latter's conversion to Christianity.

[25] In exchange of his new fief, Rollo swore loyalty to the King of West Francia, was baptized and promised to defend the Seine's estuary from other Viking raiders.