They recognized a common king as a common struggle changed AElfred and his sons from mere leaders of West-Saxons into leaders of all Englishmen in their fight with the stranger.

And when the work which AElfred set his house to do was done, when the yoke of the northman was lifted from the last of his conquests, Engle and Saxon, Northumbrian and Mercian, spent with the battle for a common freedom and a common country, knew themselves in the hour of their deliverance as an English people.
The new people found its centre in the King.

The heightening of the royal power was a direct outcome of the war.

The dying out of other royal stocks left the house of Cerdic the one line of hereditary kingship.

But it was the war with the northmen that raised AElfred and his sons from tribal leaders into national kings.