This circular earthwork, measuring roughly 25 metres across at its base and rising up to 3.2 metres high, sits on a triangular point with the sea to the west and a natural valley to the east. Known locally as Haarian’s Moat, this mound is believed to be where the Anglo-Norman invasion of Ireland began in May 1169, when Robert FitzStephen and Maurice de Prendergast landed with a force of about 300 men and likely fortified their position with a motte.

The mound’s strategic location on Bannow Island made perfect sense for those first invaders. The island, roughly 1.4 kilometres long and 600 metres at its widest, once guarded the eastern side of the entrance to Bannow Bay, a shallow triangular inlet stretching 7 kilometres inland. Today, sand bars have dramatically altered the landscape; the western entrance has narrowed considerably whilst the island itself has become attached to the eastern shore, making it no longer a true island at all.

Whilst the earthwork has traditionally been interpreted as a defensive motte, some scholars have suggested it might actually be a pillow mound or rabbit warren, with the name Haarian possibly deriving from the Irish ‘Hare-een’, meaning little hare or rabbit. The absence of a defensive fosse (ditch) around the mound supports this alternative theory, though a north-south trench on the western side and a farm laneway cut into the northern slope have modified the original structure. About 170 metres to the southeast, across the small valley, stands a church, suggesting this area remained important to the local community long after those first Norman boots hit Irish soil.