In 920 Sitric left Dublin for Northumbria, with his kinsman Gofraid ua Ímair succeeding him as king. That same year he led a raid on Davenport, Cheshire, perhaps as an act of defiance against Edward the Elder, King of the Anglo-Saxons. In 921 Ragnall ua Ímair died, with Sitric succeeding him as King of Northumbria. Though there are no written accounts of conflict, numismatic evidence suggests there was a Viking reconquest of a large part of Mercia in the following few years. An agreement of some sort between the Vikings of Northumbria and the Anglo-Saxons was achieved in 926 when Sitric married a sister of Æthelstan, perhaps Edith of Polesworth. Sitric also converted to Christianity, though this did not last long and he soon reverted to paganism. He died in 927 and was succeeded by his kinsman Gofraid ua Ímair. Sitric's son Gofraid later reigned as King of Dublin, his son Aralt as King of Limerick, and his son Amlaíb Cuarán as king of both Dublin and Northumbria.
The ruling Vikings of Dublin were expelled from the city in 902 by a joint force led by Máel Finnia mac Flannacán, overking of Brega and Cerball mac Muirecáin, overking of Leinster. Those Vikings that survived the capture of the city split into different groups; some went to France, some to England, and some to Wales. Archaeological evidence suggests Dublin remained occupied in the years immediately following this expulsion, perhaps indicating only the ruling elite were forced to leave. However, Viking raids on Irish settlements continued, and in 914, a large Viking fleet travelled to Waterford. The arrival of this fleet marked the re-establishment of Viking rule over parts of Ireland, and was followed by more Vikings settling in Limerick the following year.
The main historical sources for this period are the Norse sagas and the Irish annals. Some of the annals, such as the Annals of Ulster, are believed to be contemporary accounts, whereas the sagas were written down at dates much later than the events they describe and are considered far less reliable. A few of the annals such as the Fragmentary Annals of Ireland and the Annals of the Four Masters were also complied at later dates, in part from more contemporary material and in part from fragments of sagas. According to Downham: "apart from these additions [of saga fragments], Irish chronicles are considered by scholars to be largely accurate records, albeit partisan in their presentation of events".