The most visible reminder of this medieval power shift stands just north of Aghaboe Abbey: a substantial motte that once served as a fortified stronghold for the new Norman rulers.

The earthwork is a classic example of Norman military architecture in Ireland, featuring a slightly squared-off mound roughly 35 metres across at its summit and 42 metres at its base. A grass-covered stone wall still rings the top of the motte, though centuries of weather and neglect have worn it down considerably. The structure sits within a shallow fosse, or defensive ditch, about 8.6 metres wide but now only a metre deep; time has filled in what was once a more formidable barrier. To the north, you can still make out the remains of a bailey, the enclosed courtyard that would have contained buildings for soldiers, servants, and storage, defined by a scarp that stretches about 23.5 metres north to south.

This motte and bailey castle represents the standard Norman approach to controlling newly conquered territories: quick to build using local labour and materials, yet effective enough to dominate the surrounding landscape. The choice to position it near the already ancient Aghaboe Abbey was no accident; the Normans often built their fortifications close to existing religious sites, both to control important centres of population and to legitimise their rule through proximity to established sacred spaces.