The "Viking" link to the Normans however is quite often overstated.

It is certainly true enough that William was a direct descendant of Rollo, and that many Norse had come to settle in Normandy, but not all of these had been Vikings. Viking was a job rather than an ethnicity, and not every Scandinavian that came to Normandy did so as a Viking (sea raider / pirate). There were also merchants, fishermen, tradesmen, farmers, ect.

Second, the Norse settlement tended to be localized in certain places in Normandy like Rouen, and on the whole the native Franks of Normandy were not displaced and remained the majority. It was not too dissimilar to the later Norman conquest of England in that regard. Almost immediately there was also a great deal of interrmarriage between the Franks and the Norse, including with Rollo himself. By the time you get to 1066 that Norse minority had long since been absorbed by the Frankish majority, and the Normans spoke a dialect of French. The Normans in 1066, in short, were much more French than Norse. They also called themselves Franks.

Finally, most of the army William took with him to England wasn't even recruited in Normandy. Normans held the center of the field at Hastings but the left was composed of Bretons and the right men from other regions of France like Picardy or Boulogne, as well men as from Flanders.