The Chancellor, in pursuance of a deliberate plan for maintaining the royal power, was engaged in taking into his own hands the many castles which since the death of Henry II. had got into untrustworthy keeping. The importance of this measure, sufficiently clear from the history of the two last reigns, justified some severity. Yet action so speedy and direct could scarcely have been expected by men who had only a year and a half before paid down large sums of money to Richard for the possessions of which they were now deprived. John knew this; he knew that he had himself been kept out of the castles belonging to the lordships which were showered upon him, and determined to avail himself of the first chance to set matters right and to obtain recognition of his brother’s heir. So whilst Longchamp was busy in the West of England John took measures for securing the castles of Tickhill and Nottingham, the two strongest fortresses to which he thought he had a claim. The chance soon came. [Sidenote: Gerard Camvill. ] [Sidenote: War and truces. ] [Sidenote: Mission of Walter of Coutances. ] Gerard Camvill, the warden of Lincoln Castle and sheriff of the shire, refused to surrender his fortress at the command of Longchamp, and appealed to John as his liege lord. John took up arms and seized Nottingham and Tickhill. The Chancellor went northward to meet him, but no battle was fought; and a truce was made at Winchester towards the end of April, 1191. This lasted but a short time. Soon after the pacification, about midsummer, war broke out again; again the castles were surrendered to John, and a battle was imminent. But now a new actor appeared. Richard, hearing from his mother of the angry state of the kingdom, sent from Messina the Archbishop of Rouen, Walter of Coutances, an old officer of the English court who had been Vice-Chancellor to Henry II., with instructions of which we have no very certain account, but which probably contained two or three alternative courses, one of which was the superseding of Longchamp. Just at the same time Clement III. died, and it was very uncertain whether Celestine III., who succeeded him, would renew the legatine commission. The Archbishop of Rouen arrived in time to prevent bloodshed; but he did not produce his summary instructions. A second truce was made at Winchester in July, and the castles both of the king and of John were placed in safe hands. [Sidenote: Return of Archbishop Geoffrey. ] [Sidenote: Longchamp removed from the Justiciarship. ]