captured by the Matilda's forces on 2 February 1141, David finally decided to disregard his agreement with Stephen and seek the support of Matilda. In either May or June, David travelled to the south of England to enter Matilda's company, and was present for her expected but aborted coronation at Westminster Abbey. David was there until September when the Empress found herself surrounded at Winchester. This civil war, or "the Anarchy" as it was later called, enabled David to strengthen his own position in northern England. While David consolidated his hold on his own and his son's newly acquired lands, he also sought to expand his influence. The castles at Newcastle and Bamburgh were again brought under his control, and he attained dominion over all of England north-west of the River Ribble and Pennines, while holding the north-east as far south as the River Tyne, on the borders of the core territory of the bishopric of Durham. While his son brought all the senior barons of Northumberland into his entourage, David rebuilt the fortress of Carlisle. Carlisle quickly began replacing Roxburgh as his favoured residence. David's acquisition of the mines at Alston on the South Tyne enabled him to begin minting the Kingdom of Scotland's first silver coinage. David, meanwhile, issued charters to Shrewsbury Abbey in respect to their lands in Lancashire. Bishopric of Durham and the Archbishopric of York However, David's successes were in many ways balanced by his failures. David's greatest disappointment during this time was his inability to ensure control of the bishopric of Durham and the archbishopric of York. David had attempted to appoint his chancellor, William Comyn, to the bishopric of Durham, which had been vacant since the death of Bishop Geoffrey in 1140. Between 1141 and 1143, Comyn was the de facto bishop, and had control of the bishop's castle; but he was resented by the chapter. Despite controlling the town of Durham, David's only hope of ensuring his election and consecration was gaining the support of the Papal legate, Henry of Blois, bishop of Winchester and brother of King Stephen. Despite obtaining the support of the Empress Matilda, David was unsuccessful and had given up by the time William de St Barbara was elected to the see in 1143. David also attempted to interfere in the succession to the archbishopric of York. William FitzHerbert, nephew of King Stephen, found his position undermined by