This elusive fortress belonged to the White Knight, a title held by the FitzGibbon family who controlled much of County Limerick during the medieval period. The castle’s documented history spans from 1579, when it was granted to T. Burgeate along with its manor and mill, through various changes of ownership including grants to G. Beston and Laurence Bostock in 1587, and later to Edmund FitzGibbon in 1590.

By the late 16th century, the castle was already showing signs of decay. A 1590 grant describes it as having a ruinous court, though it was still surrounded by a stone wall. The decline continued into the 17th century; by 1617, Maurice Hurley of Knocklong had settled what was then described as a ruined castle with its water mill and a small garden called Garrenruddery. The 1655 and 1659 Civil Surveys paint a picture of complete abandonment, recording an old ruinous castle and waste mill seat on the River Loobagh, bordered by the river to the west, Dominican Abbey lands to the south, John Fox’s garden to the east, and Richard Creagh’s meadow to the north.

A map from around 1600 housed in Trinity College Dublin shows a castellated building on the east bank of the River Loobagh, opposite Kilmallock Mill and just south of another watermill. This structure might well be Courtneruddery, standing as a silent witness to the rise and fall of the White Knights’ power in Limerick. Though the physical castle has vanished, these historical fragments preserve the memory of a once significant stronghold that guarded the approaches to Kilmallock during Ireland’s turbulent medieval and early modern periods.