The first reliable report of Máel Coluim's reign is of an invasion of Bernicia in 1006, perhaps the customary crech ríg (literally royal prey, a raid by a new king made to demonstrate prowess in war), which involved a siege of Durham.

This appears to have resulted in a heavy defeat by the Northumbrians, led by Uhtred of Bamburgh, later Earl of Bernicia, which is reported by the Annals of Ulster.

A second war in Bernicia, probably in 1018, was more successful.

The Battle of Carham, by the River Tweed, is a victory for the Scots led by Máel Coluim and the men of Strathclyde led by their king, Owen the Bald.

By this time, Earl Uchtred may have been dead, and Eiríkr Hákonarson had been 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 takes no action against the Scots so far as is known.

The work De obsessione Dunelmi (The siege of Durham, associated with Symeon of Durham) claims that Uchtred's brother Eadwulf Cudel surrendered Lothian to Máel Coluim, presumably in the aftermath of the defeat at Carham.

This is likely to have been the lands between Dunbar and the Tweed as other parts of Lothian had been under Scots control before this time.

It has been suggested that Cnut received tribute from the Scots for Lothian, but as he had likely received none from the Bernician Earls this is not very probable.

The defendable position, flow of money from pilgrims, and power embodied in the church at Durham ensures that a town forms around the cathedral, establishing the early core of the modern city.

A very simple temporary structure to house the relics of Cuthbert at Durham had been built initially from local timber.

The shrine was then transferred to a sturdier, probably wooden, building known as the White Church.

This church was itself replaced three years later in 998 by a stone building also known as the White Church, which had been completed by 1018 apart from its tower.

Durham will soon become a site of pilgrimage, encouraged by the growing cult of Saint Cuthbert.

King Cnut is one such early pilgrim, granting many privileges and much land to the Durham community.

The lack of Norman response appears to have caused the Northumbrians to grow restive, and in the spring of 1080 they rebel against the rule of Walcher, the Bishop of Durham and Earl of Northumbria.

Walcher, a priest in Lotharingia from Liege and a secular clerk, had been invited by William I to fill the post of Bishop of Durham, and he had been consecrated bishop in 1071 and probably enthroned on April 3 of that year.

During the first part of his term as bishop, he had been on friendly terms with Waltheof earl of Northumbria, so much so that Waltheof sat with the clergy when Walcher held synods.

After Waltheof rebelled and lost his earldom, Walcher had been allowed to buy the earldom.

Walcher plans to introduce monks into his cathedral chapter, and will be remembered as encouraging monasticism in his diocese.

Particularly, he is known as the patron of Aldwine, who attempts to reestablish monasticism at Whitby.

Eventually, the group settles at Durham under Walcher's successor William de St-Calais.

The medieval chronicler Symeon of Durham states that Walcher had begun construction of monastic buildings at Durham as part of his plan to introduce monks into Durham.

One of Walcher's counselors is Ligulf of Lumley, who is connected by birth to the old Northumbrian line and is married to the daughter of Ealdred, Earl of Bernicia.

Ligulf's presence in the bishop's council provides a link with the local aristocracy.

There is a Scottish invasion in 1079, which Walcher is unable or unwilling to deal with effectively.

The Scots, under Malcolm III, are able to plunder Northumberland for about three weeks unopposed before returning to Scotland with slaves and booty.

Ligulf is very critical of Walcher's conduct.

A feud ensues between Ligulf and two of Walcher's henchmen, his chaplain Leobwin and his kinsman Gilbert.

Gilbert attacks Ligulf's hall in the middle of the night and Ligulf and most of his household are killed.

The Northumbrians are enraged at the murder of one of their leaders and there is a real threat of rebellion.

Walcher, in order to calm the situation, agrees to travel from Durham and meet Ligulf's kinsmen at Gateshead.

…County Palatine of Durham, …

The present Durham Cathedral, replacing an earlier church erected to house the relics of the seventh-century-era Saint Cuthbert, had been designed and built under William of St. Carilef (or William of Calais) who had been appointed as the first prince-bishop by William the Conqueror in 1080.

Since that time, there have been major additions and reconstructions of some parts of the building, but the greater part of the structure remains true to the Norman design.

Construction of the cathedral begins in 1093 at the eastern end.

The three-towered cathedral’s Latin cross plan calls for the innovative use of pointed arches and stone ribbed groin vaults that will allow the use of windows to admit light directly into the nave.

This scheme will overcome the problem of dark, windowless naves (as, for example, in the contemporaneous church of Saint Sernin in Toulouse) that receive only indirect light from small windows along the side aisles.

Edgar claims the kingship in early 1095.

His older brother Edmund sides with Donald, presumably in return for an appanage and acknowledgment as the heir of the aging and son-less Donald.

Edgar receives limited support from William II as Duncan had before him; however, the English king is occupied with a revolt led by Robert de Mowbray, Earl of Northumbria, who appears to have had the support of Donald and Edmund.

Rufus campaigns in northern England for much of 1095, and during this time Edgar gains control only of Lothian.

A charter issued at Durham at this time names Edgar "... son of Máel Coluim King of Scots ... possessing the whole land of Lothian and the kingship of the Scots by the gift of my lord William, king of the English, and by paternal heritage."

Edgar's claims have the support of his brothers Alexander and David—Ethelred is Abbot of Dunkeld, and Edmund is divided from his siblings by his support of Donald—and his uncle Edgar Ætheling as these witness the charter at Durham.

The construction of Durham Cathedral is the best-known legacy of the late William de St. Calais, Bishop of Durham, although the nave will not be not finished until 1130.

The cathedral displays such characteristically Norman architectural features as high vaults atop windowed clerestories.

The construction technique of combining a pointed arch with another rib allows a six-pointed vault, which enables the building to attain a greater height than earlier churches.

This permits larger celestory windows, and lets more light into the building.

The technique of the six-pointed vault will spread to Saint-Etienne in Caen from which it will influence the development of early Gothic architecture near Paris.

The system of rib vaulting in the choir, completed in 1104, is the earliest consistent use of this technique in Europe.

The choir of Durham Cathedral had been completed by 1096 and work has proceeded on the transepts and nave, of which the walls were finished by 1128, and the high vault complete by 1135.

Matilda's uncle, David I of Scotland, invades the north of England on the news of Henry's death.

David I crosses the border and reaches Durham in January 1136, during the first months of the reign of Stephen.