This imposing rectangular tower, measuring 11.6 by 8 metres, was meticulously documented in 1840 when much of its medieval character remained intact, including original glass in several windows and ornamental cut stone surrounds. The structure consists of three storeys topped by a corner turret that reaches an additional 30 metres skyward, with walls nearly four feet thick built from regular stones bonded with lime mortar. Most intriguingly, the third storey contains what appears to have been a chapel, complete with a piscina for washing sacred vessels and space for an altar within a large window embrasure, alongside a chimney piece bearing the date 1638 and religious inscriptions.

The castle’s turbulent history reflects the broader conflicts of medieval and early modern Ireland. Local tradition attributes its construction to the Knights Templars, hence the name Knightstreet, though records show it passing through various hands including the Byboys family in the 13th century and the de Lacy family by the 16th century. During the Desmond Rebellions of 1569, the castle endured a bloody siege when Captain Warde’s forces stormed it and slaughtered all forty defenders who had held it for the Desmond cause. John Lacy, the owner, was later attainted for treason in 1583, and the castle changed hands multiple times through confiscation and grants until it was burned by Irish forces retreating from Newcastle in 1691.

The 19th century brought an unlikely renaissance when Reverend Thomas Gibbings restored the medieval tower in 1821 as a temporary residence whilst his glebe house was under construction, earning it the nickname “Parson’s Castle”. During the violent Rockite troubles of the 1820s, when agrarian secret societies terrorised the countryside, the sturdy tower served as a military barracks. It later functioned as an auxiliary hospital before declining into agricultural use; by 1905 it had been ignominiously reduced to a cow house with stalls built against its ancient walls. Despite these indignities, the castle retained its graceful proportions and stepped battlements, with a spiral stair connecting the entrance and cellar to the hall, whilst a second stair, cleverly squinched over a re-entrant angle, led to the battlements past a wing containing a latrine and bedchamber.