This elusive fortress appears in medieval records dating back to 1218, when Walter de Lacy held it alongside properties in Drogheda and Ardmayle, County Tipperary. The castle was apparently one of forty fortifications granted to the citizens of Limerick by King John, though frustratingly, none of these structures left any trace that early twentieth-century scholars could identify. Between 1213 and 1228, the citizens granted the castle and a carucate of land to Henry de Londres, Archbishop of Dublin, and the Church of the Holy Trinity, marking the beginning of a long chain of ownership that would stretch into the seventeenth century.

The historical record offers tantalising glimpses of the castle’s later fate. Before 1248, the Archbishop granted it to Matilda, wife of W. de Mareys, and by the 1620s, the property had passed to Sir William Parsons, who received confirmation of his ownership of “Castleblake or Castleblagh in the County of the City of Limerick” in 1624. Nicholas Arthur held it in 1633 and 1655, and Sir William Petty received confirmation of the lands in 1666. Intriguingly, whilst the castle doesn’t appear on Petty’s maps, the 1657 Down Survey barony map of the North Liberties shows two buildings immediately south of the road leading into Limerick City, in roughly the same location where Ordnance Survey maps would later mark the castle site.

Today, modern housing covers the area where Victorian cartographers placed Castle Blake, somewhere in or near what became the North Liberties of Limerick; a district that was eventually formed into its own barony. The castle’s precise location remains debatable, though it must have stood close to the city and adjoining the forty carucates of burgage land granted by King John. Early twentieth-century antiquarians like Westropp and Orpen connected it with the townland of Farranshone, which still retains its name, albeit as a disjointed fragment of its former self. Whether any physical traces of this medieval stronghold survive beneath the streets and houses of modern Limerick remains an open question, a reminder that even in well-documented landscapes, some historical mysteries refuse to yield their secrets.