David I, king of Scotland from 1124 to 1153, was a combination of administrator, church patron and freebooter. He invaded the north of England in 1138 to further his family's interests as English landowners, as well as his own as king of Scots, especially in the country between Forth and Tyne which was then almost as Scottish as it was English.

This provoked the nearest thing to spontaneous, popular resistance since the Viking invasions some 250 years earlier. He swept south from Northumberland, to which he had legitimate claims, into Yorkshire with such needless, gleeful violence that he forfeited any complicity he might have expected from the English barons, all of whom joined forces with the local militia to rout the Scots near Northallerton.

The English fought under the banners of their patron saints, waging a holy war against a barbarian, even heathen race. The half-naked men of Galloway were singled out as being especially depraved. They were considered so foreign that they were often picturesquely (but inaccurately) described as 'Picts' rather than 'Scots'. David and his eldest sont gained considerably from their campaign. By 1149 they had extended their lordship, if temporarily, over lands stretching to the Ribble and Tyne and beyond.