Oswald was the son of Æthelfrith of Bernicia and came to rule after spending a period in exile ; after defeating the British ruler Cadwallon ap Cadfan, Oswald brought the two Northumbrian kingdoms of Bernicia and Deira once again under a single ruler, and promoted the spread of Christianity in Northumbria.

The land once part of Northumbria at its peak is now divided by modern administrative boundaries:

The next king, Æthelred defeated Northumbria in the Battle of the Trent in 679, settling once and for all the long disputed control of the former kingdom of Lindsey.

Both reverted to paganism, and both were killed by Cadwallon ; eventually Eanfrith's brother Oswald defeated and killed Cadwallon and united Northumbria once more.

Bede tells of Æthelfrith's great successes over the Britons, while also noting his paganism ( the conversion of Northumbria did not begin until a decade after his death ): he " ravaged the Britons more than all the great men of the English, insomuch that he might be compared to Saul, once king of the Israelites, excepting only this, that he was ignorant of the true religion.

To the south, in the Kingdom of England, the Earls of Bernicia and Northumbria, whose predecessors as kings of Northumbria had once ruled most of southern Scotland, still controlled large parts of the south-east.

Respect for the saint did not mean that Malcolm refrained entirely from raiding the north ; he was killed in 1093 while once more raiding Northumbria.

Northumberland means " country north of the River Humber and is related to the name " Northumbria " which refers to the old Anglo-Saxon kingdom which once covered much of Northern England.

The combined kingdom became known as the kingdom of Northumbria: it stretched from the River Humber in the south to the River Forth in the north.

The former kingdom of Northumbria stretched from the Humber and Mersey estuaries, northward to the Firth of Forth, where, passing the western Kingdom of Strathclyde, it met the Kingdom of Alba ( Scotland ).

While the kingdoms of East Anglia, Mercia and Northumbria were under attack, other Viking armies were active in the far north.

Eric Bloodaxe took York in 948, before being driven out by Edred, and when Amlaíb Cuaran again took York in 949 – 950, Máel Coluim raided Northumbria as far south as the Tees taking " a multitude of people and many herds of cattle " according to the Chronicle.

Thus, Northumbria became not only part of modern England's far north, but also covered much of what is now the south-east of Scotland.

In Cuthbert's time the Anglo-Saxon Kingdom of Northumbria included, in modern terms, northern England as well as south-eastern Scotland as far north as the Firth of Forth.

Gwynedd was the most powerful of these kingdoms in the 6th century and 7th century, under rulers such as Maelgwn Gwynedd ( died 547 ) and Cadwallon ap Cadfan ( died 634 / 5 ) who in alliance with Penda of Mercia was able to lead his armies as far as Northumbria and control it for a period.

Northumbrian Old English had been established in what is now southeastern Scotland as far as the River Forth by the seventh century, as the region was part of the Anglo-Saxon kingdom of Northumbria.

Peace negotiations followed later that year to that effect that Edmund accepted Amlaíb as an ally and as two northern sources add, ceded to him Northumbria as far south as Watling Street.

The Chronicle of the Kings of Alba records that shortly thereafter, in ' 948 or 949, Malcolm ( I ) of Scotland and Cumbria, at Constantine's instigation, raided Northumbria as far south as the River Tees and returned with many cattle and captives.

Aldhelm was the first Anglo-Saxon, so far as we know, to write in Latin verse, and his letter to Acircius ( Aldfrith or Eadfrith, king of Northumbria ) is a treatise on Latin prosody for the use of his countrymen.

At the far north are the Picts, then below them Strathclyde and Northumbria.

An alternative northern location is at Bassington on the River Aln in Northumbria, not far from the River Glen.

" The Chronicle further states that Kenneth plundered Northumbria three times, first as far as Stainmore, then to Cluiam and lastly to the River Dee by Chester.

By this time Earl Uchtred may have been dead, and Eiríkr Hákonarson was appointed Earl of Northumbria by his brother-in-law Cnut the Great, although his authority seems to have been limited to the south, the former kingdom of Deira, and he took no action against the Scots so far as is known.

That year Máel Coluim mac Domnaill, the king of Alba, raided Northumbria as far south as the River Tees, capturing many slaves and much loot.

At the time of the Domesday Book in 1086 most of the future county remained part of Scotland although some villages in the far south west, which were the possessions of the Earl of Northumbria, were included in the Yorkshire section with the Furness region.

Siward himself died in 1055, and Waltheof being far too young to succeed as Earl of Northumbria, King Edward appointed Tostig Godwinson to the earldom.

For while Bede is loyal to Northumbria he shows an even greater attachment to the Irish and the Irish Celtic missionaries, whom he considers to be far more effective and dedicated than their rather complacent English counterparts.

In the late 6th and early 7th centuries, the kingdom of Northumbria extended as far south as the River Mersey, south of what was then the settlement of Manchester.

It was spoken as far north as Staffordshire, bordering Northumbria and Strathclyde, and as far south as South Oxfordshire / Gloucestershire, where it bordered Wessex.

The important artistic centres, in so far as these can be established, were concentrated in the extremities of England, in Northumbria, especially in the early period, and Wessex and Kent near the south coast.

The Kingdom of Northumbria in the far north of England was the crucible of Insular style in Britain, at centres such as Lindisfarne, founded c. 635 as an offshoot of the Irish monastery on Iona, and Monkwearmouth-Jarrow Abbey ( 674 ) which looked to the continent.

In 1067 Bleddyn and Rhiwallon joined with the Mercian Eadric the Wild in an attack on the Normans at Hereford, ravaged the lands as far as the River Lugg then in 1068 allied with Earls Edwin of Mercia and Morcar of Northumbria in another attack on the Normans.

Kenneth's son Constantine died in 876, probably killed fighting against a Viking army which had come north from Northumbria in 874.

Northumbria may have been divided by this time between the Viking kings in York and the local rulers, perhaps represented by Eadulf, based at Bamburgh who controlled the lands from the River Tyne or River Tees to the Forth in the north.

* 1054 – Siward, Earl of Northumbria invades Scotland and defeats Macbeth, King of Scotland somewhere north of the Firth of Forth.

While marching north again, Malcolm was ambushed by Robert de Mowbray, Earl of Northumbria, whose lands he had devastated, near Alnwick on 13 November 1093.

This defeat meant that an exiled member of the Deiran royal line, Edwin ( Acha's brother ), became king of Northumbria ; Oswald and his brothers fled to the north.

Northumbria lost control of Mercia in the late 650s, after a successful revolt under Penda's son Wulfhere, but it retained its dominant position until it suffered a disastrous defeat at the hands of the Picts at the Battle of Dun Nechtain in 685 ; Northumbria's king, Ecgfrith ( son of Oswiu ), was killed, and its power in the north was gravely weakened.

Tostig was helped into the earldom of Northumbria, thus controlling the north.

They soon moved north and in 867 captured Northumbria and its capital, York, defeating both the recently deposed King Osberht of Northumbria, as well as the usurper Ælla of Northumbria.

From there they moved north and attacked Northumbria, which was in the midst of a civil war between the deposed king Osberht and a usurper Ælla.

The area occupied by the Danelaw was roughly the area to the north of a line drawn between London and Chester, excluding the portion of Northumbria to the east of the Pennines.

Threatened by Harold's fleet, Tostig moved north and raided in East Anglia and Lincolnshire, but he was driven back to his ships by the brothers Edwin, Earl of Mercia, and Morcar, Earl of Northumbria.

Indeed, the name Northumbria came from Anglo-Saxon Norðhymbre ( plural ) = " the people north of the Humber ".

This defeat severely weakened Northumbrian power in the north and Bede dates the beginning of the decline of the kingdom of Northumbria from Ecgfrith's death.

The larger neighbouring kingdoms included Northumbria to the north, recently united from its constituent kingdoms of Bernicia and Deira, East Anglia to the east, and Wessex, the kingdom of the West Saxons, to the south.

While marching north again, Malcolm was ambushed by Robert de Mowbray, Earl of Northumbria, whose lands he had devastated, near Alnwick on 13 November 1093.

Later, in 1095, an English noble, Robert de Mowbray, who was Earl of Northumbria, challenged the bishop's authority in the north.

While Edmund certainly controlled Northumbria after Amlaíb was expelled and Ragnall killed, he may soon after have lost control of the north to a Scandinavian king named Eiríkr, usually identified with Eric Bloodaxe.