Viking raiders in 853 had first established a settlement near present Waterford.

It and all the other longphorts had been vacated in 902, the Vikings having been driven out by the native Irish.

The Vikings, led at first by Ottir Iarla (Jarl Ottar), return in 914  to conquer much of Ireland.

Ottir is particularly associated in Ireland with raiding and conquests in the province of Munster.

The Cogad Gáedel re Gallaib describes him raiding there alongside Ragnall and associates this with the Viking settlement of Cork.

Their base for this activity is Loch dá Caech or present day Waterford.

Later the same epic describes Ottir conquering the eastern part of Munster from his seat at Waterford, but it is unclear if he ruled it as king outright or was in any way subject to Ragnall, because the annals offer a different chronology.

The Ímar from whom the Uí Ímair are descended is generally presumed to be that Ímar, "king of the Northmen of all Britain and Ireland", whose death is reported by the Annals of Ulster in 873.

Whether this Ímar is to be identified with the leader of the Great Heathen Army or with Ivar the Boneless is less certain.

In the period between the death of Ímar and the expulsion of the Northmen and Norse-Gaels from Dublin in 902, it is not certain that any descendants of Ímar played a notable part in the politics of the region.

Members of the kindred appear to have led armies against the Picts following their expulsion, but these were killed and the armies destroyed in 904 by Constantín son of Áed, the king of Alba.

In the following decade, it is supposed that the grandsons of Ímar may have been in some part of the Atlantic or Irish Sea coasts of Britain where the historical record sheds almost no light on events, the area in question extending from the Isle of Man through the Hebrides to the Northern Isles, as well as the coasts opposite.

They reappear again in 914 when Ragnall and his kinsman Sihtric Cáech are recorded leading fleets in the Irish Sea.

Ragnall defeats the fleet of a certain Barid son of Ottar off the Isle of Man in thus year.

Some historians place the first Battle of Corbridge in this year, following the account in the Historia de Sancto Cuthberto, which can be read as implying two battles, and propose that Ragnall became king of Northumbria in 914 or before.

The Battle of Tempsford takes place in a fortified Danish burh where, following an unsuccessful attack on Bedford, the Danes are defeated in 917 by an English army led by King Edward the Elder, who kills their king and ends organized Danish resistance.

The Historia de Sancto Cuthberto states that Ealdred "was a friend of King Edward the Elder, as his father had been a favorite of King Alfred the Great".

Ealdred had been driven from his lands, whether all of Northumbria or merely the northern part which had once been Bernicia is debated, by Ragnall ua Ímair, either in or before 914, or alternatively as late as 918.

The Historia states that Ealdred sought refuge with Constantín mac Áeda, the king of Alba, and that the two fought Ragnall at the battle of Corbridge, dated to 918 by the Annals of Ulster and the Chronicle of the Kings of Alba.

The battle appears to have been indecisive and Ragnall remained the master of at least southern Northumbria, former Deira, or perhaps of all.

The Annals of Ulster informs us that the Norse army divided itself into four columns, in one of which may have been Ottir Iarla, a longtime ally of Ragnall.

The Scots destroy the first three but are ambushed by the last, commanded by Ragnall himself, which had remained hidden behind a hill.

The Scots manage to escape without disaster, however.

The Historia de Sancto Cuthberto adds that the English fought alongside the Norse, though it ignores the presence of the Scots.

All of the Danes south of the Humber by 918 have submitted to Edward.

The former Anglo-Saxon kingdom of East Anglia, since 886 a part of the Danelaw, now becomes an English earldom.

Edward, the brother of Æthelflæd, the Lady of the Mercians, incorporates English Mercia into Wessex following her death in 918.

Edward has by this time virtually extinguished Danish power in England.

Edward the Elder in 919 builds Bedford’s first known fortress, on the south side of the River Ouse, and here receives the area's submission.

Ragnall, descending on York in 919, takes the city and has himself proclaimed king.

The Bernicians remain under him, though Ealdred of Northumbria and Dyfnwal II, king of Strathclyde, do homage to the king of England.

Edward receives the formal submissions, all in the year 920, of Raegnald, the Irish-Norse king of York; Ealdred, ruler of English Northumbria; the Welsh king of Strathclyde; and (possibly) Constantine II of Scotland.

The Norse, the Scots and the Welsh by the end of Edward's reign have acknowledged him as "father and lord".

This recognition of Edward's overlordship in Scotland will lead to his successors' claims of suzerainty over that Kingdom.

The Viking king Sihtric rules the Kingdom of York in southern Northumbria, but Ealdred maintains Anglo-Saxon rule in at least part of the former kingdom of Bernicia from his base in Bamburgh in northern Northumbria.

King Constantine rules Scotland, apart from the southwest, which is the British Kingdom of Strathclyde.

Wales is divided into a number of small kingdoms, including Deheubarth in the southwest, Gwent in the southeast, Brycheiniog immediately north of Gwent, and Gwynedd in the north.

Edward has reorganized the Church in Wessex, creating new bishoprics at Ramsbury and Sonning, Wells and Crediton.

Despite this, there is little indication that Edward was particularly religious.

In fact, the Pope had delivered a reprimand to him to pay more attention to his religious responsibilities.

Having unified most of England south of the Humber River and largely restored the Danelaw to English rule (although Danish laws and customs persist there), Edward dies on July 17, 924, at Farndon-Upon-Dee leading an army against a Welsh-Mercian rebellion.