11th century thumb|Plan of the castle in the 21st century; A – North Gate; B – motte and shell keep; C – outer bailey; D – main lodgings; E – inner bailey; F – the Clock Tower; G – the Black Tower; H – South Gate and barbican tower The Normans began to make incursions into South Wales from the late 1060s onwards, pushing westwards from their bases in recently occupied England. Their advance was marked by the construction of castles, frequently on old Roman sites, and the creation of regional lordships.; The reuse of Roman sites produced considerable savings in the manpower required to construct large earth fortifications.
11th century thumb|Plan of the castle in the 21st century; A – North Gate; B – motte and shell keep; C – outer bailey; D – main lodgings; E – inner bailey; F – the Clock Tower; G – the Black Tower; H – South Gate and barbican tower The Normans began to make incursions into South Wales from the late 1060s onwards, pushing westwards from their bases in recently occupied England. Their advance was marked by the construction of castles, frequently on old Roman sites, and the creation of regional lordships.; The reuse of Roman sites produced considerable savings in the manpower required to construct large earth fortifications.