Royal concerns over security led to Henry II investing heavily in a new castle structure on the site between 1171 and 1174. It was unusual for a new royal castle to be built in this part of England during the 12th century, and Henry appears to have been driven by the military threat from Scotland before and during the Great Revolt of 1173 to 1174. Henry II spent almost £600 on the castle between 1170 and 1187, most of it in the first few years, rebuilding the older structure under the supervision of the Count of Brittany's local tenants, Torfin, Osbert and Stephen of Barningham.