At the start of this period, war was primarily a matter of plunder, destruction and skirmishing. The difficulties inherent in an attack on even minor fortifications simply intensified this. Ravaging undermined the economic base of the castle-owner and the morale of its garrison. The presence of a castle which could afford shelter to the defeated in battle added to the disincentives of risking men and political capital in the open field. This situation enabled substantial families who settled away from the centres of power of the great to maintain a degree of independence, by raising castles which increased their authority over the neighbouring countryside.
Sieges raised great difficulties even for the major rulers of the eleventh century. Brévol castle was the object of a bitter war in Normandy under Robert Curthose, which culminated in a set-piece siege, but its capture was a great effort involving the King of France and the Duke of Normandy. Philip I of France (1060-1108) confessed that the tower of Montlhéry had made him old before his time, while his son Louis VI cut his teeth in war against the castellan Bouchard of Montmorency. In Germany, Henry IV could not seize the fortresses of the powerful southern magnates and fought an unsuccessful war to gain control of the lands and castles of Mathilda of Tuscany. In England, the civil war under Stephen became a bitter stalemate in which castles formed the power-centres of the main parties. In 1142, Stephen's effort to push into Angevin territory by building a castle at Wilton was checked by Robert of Gloucester in a sharp battle, but shortly afterwards he seized the isolated Angevin outpost at Oxford. During this disorder, robber barons such as William de Launay, who built a castle at Ravenstone, emerged. It was only slowly and with great effort that King Stephen's superior resources began to tell, but even then a series of fortuitous deaths was almost as important in breaking the stalemate. 1