Castleknock Castle

Castleknock Castle is in Castleknock, Dublin, Ireland, and it was established by Norman settlers.

The place is recorded in early medieval Irish annals under the name Cnucha, and those records note the death of Congalach of Cnucha in 726 at his fort. In 1861 work on the grave of Reverend Thomas Plunket exposed a very large flat stone over a hollow chamber inside the castle interior, and this chamber contained a human skeleton; the feature discovered on that occasion was described as a druidic cromlech.

A Norman knight, Hugh Tyrrel, later styled Baron of Castleknock, founded the castle. He chose the summit of two esker mounds to command the route toward Dublin. Around 1171 the stronghold served as the final rallying point for Rory O’Connor during the Anglo‑Norman advance.

Richard Tyrrell, the second Baron of Castleknock, established an Abbey of St. Brigid at the site in 1184 on land where a Protestant church now stands. The monastery prospered until the dissolution of the monasteries, after which the abbey was demolished and a Protestant church replaced it.

During the Bruce campaign in Ireland, 1316 to 1317, forces under Edward Bruce captured Castleknock, took Hugh Tyrrell prisoner, and used the castle as a headquarters before releasing captives for ransom and withdrawing. In the 1640s the castle endured violent action during the wars of that decade. In 1642 it was besieged, with a contemporary account mentioning an attack by the Earl of Ormond and another describing an assault by General Monck; defenders burned valuables and suffered heavy casualties, and some survivors were executed in certain accounts. Monck left a garrison and the fortress suffered serious damage from artillery. Owen Roe O’Neill recaptured the site in 1647. After the conflict the Commonwealth government ordered the partial demolition of the battered castle and the estate was divided among private tenants.

In 1834 forty acres that included the ruins were sold to John McCann, a Vincentian friar, who founded St. Vincent’s Ecclesiastical Seminary, now St. Vincent’s Castleknock College. The ground within the old walls later became a cemetery for priests of the Society of St. Vincent de Paul and other missioners.