CHAPTER IV. OF THE POLITICAL VALUE OF CASTLES UNDER THE SUCCESSORS OF THE CONQUEROR. It is rather remarkable that castles should not occupy, even incidentally, a more prominent place in the “Domesday Survey,” as they formed a very important feature in the country; were closely, for the most part, attached to landed property; and were of great political importance. No great baron was without a castle upon each of his principal estates, nor was any bishop secure of his personal safety unless so provided. At the death of the Conqueror, it was the possession of Winchester Castle that gave to William Rufus the royal treasure, and enabled his adherents to acquire the castles of Dover and Hastings, and thus, at the commencement of his reign, to secure a safe communication with Normandy. The king, it is true, had the people on his side and owed his eventual success to their support, but the barons of his party depended largely upon their fortresses. Archbishop Lanfranc held Saltwood, which the earthworks show even then to have been strong; Willam de Warren held Lewes and Ryegate and the strong hill of Coningsburgh in Yorkshire; Chester belonged to Earl Hugh, who was supported by his fifteen barons, each of whom had his castle; and in North Wales the Earl held Diganwy, which, covered in front by the Conwy water, closed the seaward pass from that aggressive district. With the Earl and on the side of Rufus were Robert de Tilliol, who held Flint and Rhuddlan, and Scaleby and other castles on the Scottish border; while Bishop Wolstan, representing the English feeling, held his episcopal castle of Worcester against Urso d’Abitot and a swarm of Marcher barons who crossed the Severn to assail him.