Very few know that the hill nearby was once the ground over which two armies clashed in a pitched medieval battle, its date misrecorded on Ordnance Survey maps for over a century. The maps gave it as 1310; the actual date, drawn from the annals, was 20th May 1311.

The battle grew out of a bitter succession dispute within the Uí Bhriain dynasty, the ruling family of Thomond, the kingdom that covered much of what is now County Clare and north Tipperary. When Toirdhealbhach Ó Briain, king of Thomond, died in 1306, rival branches of the family went to war over the lordship. By 1311 the conflict had drawn in powerful Anglo-Norman allies on both sides. Diarmait Cléirech of Clann Bhrian was backed by Richard de Clare, who held Bunratty Castle itself. His opponent, Donnchadh of Clann Toirdhealbhaigh, had the support of William de Burgh, reinforced by men from Connacht and by John, son of Walter de Lacy, from Meath. On the day of the battle, Donnchadh and de Burgh's forces took up position on the hill adjacent to the castle, while de Clare and Clann Bhrian rode out to meet them, described in one contemporary account as emerging "as a great cloud big with fire, edged with scintillation, through the massive fortress-gates." The fighting, which appears to have taken place on the southern slopes of the hill, was ferocious: the sources speak of swords shearing and spears transpiercing, of shields raised for shelter and "many a comely visage" darkened in the press. De Burgh's side initially had the better of it, but de Burgh himself was captured while pursuing fleeing enemies. The outcome depends on which source you consult: most of the Irish annals credit Donnchadh and Clann Toirdhealbhaigh with the victory, while the Anglo-Irish annals in the Chartularies of St Mary's Abbey insist de Clare won. The contradicting accounts have never been fully reconciled, which gives the site a fittingly unresolved quality, a battle whose result still depends on whose chroniclers you trust.