sentences:  In 927, having ejected Gofraid ua Ímair from York, King Æthelstan brought Northumbria under English control.His victory in the Battle of Brunanburh in 937, in which he and his half-brother Edmund defeated Gofraid's son King Olaf (III) Guthfrithson of Dublin, seems to have had the effect of consolidating his power.This impression is borne out by royal charters issued towards the end of his reign, between 937 and 939, which style Æthelstan ruler over all Britain (e.g.