After Henry's death, David upheld his support for his niece, the former Empress-consort, Matilda, and expanded his power in northern England in the process, despite his defeat at the Battle of the Standard in 1138.
David's early career can be understood as part of Henry's frontier policy, which included marriage of two daughters to the kings of Scotland and Galloway, consolidation of royal control in the north-west coast of England and the quelling of the Montgomeries, marcher lords on the Welsh borders who had been allied to Muirchertach Ua Briain, High King of Ireland (1101–19).
His hostility to Stephen can be interpreted as an effort to uphold the intended inheritance of Henry I, the succession of his daughter, the former empress-consort Matilda.
[7] Before December was over, David marched into northern England, and by the end of January he had occupied the castles of Carlisle, Wark, Alnwick, Norham and Newcastle.
Stephen also gave the rather worthless but for David face-saving promise that if he ever chose to resurrect the defunct earldom of Northumberland, Henry would be given first consideration.
However, the first Durham treaty quickly broke down after David took insult at the treatment of his son Henry at Stephen's court.
Charter evidence shows that David had gathered in Strathclyde the four most powerful magnates in Scotland, William fitz Duncan, now lord of Moray, Máel Ísu, mormaer of Strathearn, Donnchad, mormaer of Fife and Fergus, king of Galloway, along with lesser figures such as "Dufoter" of Callendar, Máel Domnaich of Scone and Gillebrígte of Stirling, probably the toísechs or "thanes" of their respective royal demesne locations.
David advanced into the English lands taking blackmail payments from settlements and establishments that paid and plundering and burning those that did not.
[11] Richard of Hexham called it "an execrable army, savager than any race of heathen yielding honour to neither God nor man" and that it "harried the whole province and slaughtered everywhere folk of either sex, of every age and condition, destroying, pillaging and burning the vills, churches and houses".
In the summer, David split his army into two forces, sending William fitz Duncan to march into Lancashire, where he harried Furness and Craven.
The decision by David to put his small French contingent in the front line was resented by the "Galwegians", perhaps a term used for Gaels from Scotland south of the Forth rather than just from Galloway.
[24] Ailred described the same charge, saying that the first line "after their custom gave vent thrice to a yell of horrible sound, and attacked the southerns in such an onslaught that they compelled the first spearmen to forsake their post; but they were driven off again by the strength of the knights, and [the spearmen] recovered their courage and strength against the foe.
And when the frailty of the Scottish lances was mocked by the denseness of iron and wood they drew their swords and attempted to contend at close quarters" As the Scots were engaging in this close combat, Ailred tells us that the English archers began to fire on the Scottish line, causing extreme disarray and lose of life.
The suicidal bravery and endurance of the Galwegians, and the lack of Norman-style armour which Máel Ísu and the Scots had allegedly been so boastful of, was mocked by Ailred: "like a hedgehog with its quill, so would you see a Galwegian bristling all round with arrows, and none theless brandishing his sword, and in blind madness rushing forward now smite a foe, now lash the air with useless stokes".
[26] According to Henry of Huntingdon, though, the battle turned when the "chief of the men of Lothian", probably Cospatric II, earl of Dunbar, was struck by an arrow.
[25] The men of Lothian apparently fled first; and after a while, Ailred tells us the Galwegians followed suit when Domnall and Ulgric, two of their captains, were slain.
On 26 September Cardinal Alberic of Ostia arrived at Carlisle where David had called together his kingdom's nobles, abbots and bishops.
Thus, despite the surprising victory of the outnumbered English army in North Yorkshire, the series of invasions that David led into England since the death of his patron Henry at the end of 1135 had resulted in a significantly expanded kingdom.
The arrival in England of the Empress Matilda, claimant to the English throne, gave David an opportunity to renew the conflict with Stephen.
In either May or June, David travelled to the south of England to enter Matilda's company, and was present for her expected but aborted coronation at Westminster Abbey.
David's acquisition of the mines at Alston on the South Tyne enabled him to begin minting the Kingdom of Scotland's first silver coinage.
David had attempted to appoint his chancellor, William Comyn, to the bishopric of Durham, which had been vacant since the death of Bishop Geoffrey in 1140.
Despite controlling the town of Durham, David's only hope of ensuring his election and consecration was gaining the support of the Papal legate, Henry of Blois, bishop of Winchester and brother of King Stephen.
Despite obtaining the support of the Empress Matilda, David was unsuccessful and had given up by the time William de St Barbara was elected to the see in 1143.
For Oram, this event was the turning point, "the chance to radically redraw the political map of the British Isles lost forever".