During the four centuries which elapsed between the arrival of St Patrick and the establishment of a central state in Dublin by the Norsemen the history of Ireland is almost a blank as regards outstanding events.
Turgeis apparently united the Viking forces, as he is styled the first king of the Norsemen in Ireland.
The Norsemen were constantly engaged in conflict with the Irish, these cities soon became important commercial centres trading with England, France and Norway.
For some years after the death of Turgeis the Norsemen appear to have lacked a leader and to have been hard pressed.
At any rate, in 851-852 the king of Lochlann (Norway) sent his son Amlaib (Olaf the White) to assume sovereignty over the Norsemen in Ireland and to receive tribute and vassals.