His Anglo-Norman friends, the Balliols and Bruces, with the Archbishop of York, now opposed him and his son Prince Henry.

On August 22, 1138, at Cowton Moor, near Northallerton, was fought the great battle, named from the huge English sacred banner, "The Battle of the Standard." In a military sense, the fact that here the men-at-arms and knights of England fought as dismounted infantry, their horses being held apart in reserve, is notable as preluding to the similar English tactics in their French wars of the fourteenth and fifteenth centuries.
Thus arrayed, the English received the impetuous charge of the wild Galloway men, not in armour, who claimed the right to form the van, and broke through the first line only to die beneath the spears of the second.

But Prince David with his heavy cavalry scattered the force opposed to him, and stampeded the horses of the English that were held in reserve.

This should have been fatal to the English, but Henry, like Rupert at Marston Moor, pursued too far, and the discipline of the Scots was broken by the cry that their King had fallen, and they fled.

David fought his way to Carlisle in a series of rearguard actions, and at Carlisle was joined by Prince Henry with the remnant of his men-at-arms.
It was no decisive victory for England.
In the following year (1139) David got what he wanted.