The wife of David, Matilda, widow of Simon de St Liz, was heiress of Waltheof, sometime the Conqueror’s Earl in Northumberland; and to gain, through that connection, Northumberland for himself was the chief aim of David’s foreign policy,—­an aim fertile in contentions.

We have not space to disentangle the intricacies of David’s first great domestic struggles; briefly, there was eternal dispeace caused by the Celts, headed by claimants to the throne, the MacHeths, representing the rights of Lulach, the ward of Macbeth. {20} In 1130 the Celts were defeated, and their leader, Angus, Earl of Moray, fell in fight near the North Esk in Forfarshire.  His brother, Malcolm, by aid of David’s Anglo-Norman friends, was taken and imprisoned in Roxburgh Castle.  The result of this rising was that David declared the great and ancient Celtic Earldom of Moray—­the home of his dynastic Celtic rivals—­forfeit to the Crown.  He planted the region with English, Anglo-Norman, and Lowland landholders, a great step in the anglicisation of his kingdom.  Thereafter, for several centuries, the strength of the Celts lay in the west in Moidart, Knoydart, Morar, Mamore, Lochaber, and Kintyre, and in the western islands, which fell into the hands of “the sons of Somerled,” the Macdonalds.

In 1135-1136, on the death of Henry I., David, backing his own niece, Matilda, as Queen of England in opposition to Stephen, crossed the Border in arms, but was bought off.  His son Henry received the Honour of Huntingdom, with the Castle of Carlisle, and a vague promise of consideration of his claim to Northumberland.  In 1138, after a disturbed interval, David led the whole force of his realm, from Orkney to Galloway, into Yorkshire.  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.