The Viking, or more accurately Danish and Norsemen, invasions of England in the 9th century CE (865) helped lead to what ultimately would become the united country of England. Before 865, England was divided into four or sometimes more countries, populated by Angles and Saxons (or Anglo-Saxons). Wales and Cornwall were also occupied by the remaining Britons, who were the pre-Roman population of the British Isles.
These divided lands often fought each other; however, a clear dominant kingdom rarely emerged. In the 860-890s, Alfred of Wessex forged the idea of an England, one that was a united kingdom from Anglo-Saxons. This did not happen in his lifetime but by the reign of his grandson, Æthelstan, it became a reality in 927. In effect, the invasions by the Danes and Norsemen set off a series of events that ultimately led to the unification of England. After the Viking invasion, England would never be seen as having multiple states or crowns.