But the attitude of strict conformity to law was entirely compatible with that steady concentration of all real control in the King's hands, which was the leading object of Henry's policy. For this purpose the primary condition was that none of his subjects should be sufficiently powerful to challenge his authority and raise the standard of revolt, as the King-Maker and others had done in the past. The old nobility were practically wiped out. Insignificant husbands were chosen for the daughters of York. The blood of the Plantagenets ran in the veins of the house of Buckingham; but it was only in the last generation that the De la Poles had mated with the royal house, and their estates were much diminished; the Howards had suffered as supporters of Richard. Surrey indeed was deservedly restored to grace; but no amount of personal loyalty or of royal favour exempted the nobles from the severe restriction of the old practice of maintaining retainers in such numbers as to form a working nucleus for a fighting force; nor were they allowed to accumulate wealth dangerously. Henry was well pleased that his subjects should gather sufficient riches to feel a strong interest in the maintenance of order, but not enough to use it to create disorder. Beyond this, however, he was careful to employ the nobles as ministers no more than he could help. He laid the burdens of statesmanship as much as possible on the clergy--on Morton and Fox and Warham. Fox, as Bishop of Durham, played a part in the relations of England and Scotland at least as influential as that of Surrey. After Morton's death Warham became Chancellor. Yet each of these three bishops felt happier in the conduct of his ecclesiastical functions than as a minister of the Crown. All three did worthy and conscientious service, but would willingly have withdrawn from affairs of State. They were counsellors, not rulers; the one real ruler was the King himself. While the King restrained the power of the nobility as military factors in the situation, he developed his own control of military force by the revival of the militia system, always theoretically in force, but practically of late displaced by the baronial levies; and his hands were further strengthened by the possession of the only train of artillery in the realm, the value of which was markedly exemplified in the suppression of the Cornish insurgents. [Sidenote: The Star Chamber]