Castleknock () is an affluent suburb located west of the centre of Dublin city, Ireland. It is centred on the village of the same name in Fingal.
In addition to the suburb, the name "Castleknock" also refers to older units of land division: a townland, a civil parish and a barony.
Etymology
In a poem relating to the earliest centuries after Christ, the origin of the name Cnucha is connected with Conn of the Hundred Battles, and the name is said to have been borne by his foster mother: —
As the word Castle did not come into use in Ireland until Norman times we know that Castleknock is a name of comparatively recent origin. Documents from the 12th and 13th centuries refer to the place as Castrum Cnoc, simply Cnoc and also Chastel-cnoc or Castel-Cnoc. So it seems that the name Castleknock is rooted in the topography of the hill or cnoc located at the centre of the modern neighbourhood and/or the personal name of the mother of a semi-legendary High King i.e. Cnucha and the building of a castle by Normans on this site in the 12th century.
History
Gaelic period
There is some documentary evidence in chapter 72 of the Life of St. Patrick by Jocelin of Furness to support the belief that when St. Patrick had finished his visit to the City of Dubh Linn he came to Castleknock to try to convert Murinus, the local ruler of the place. Despite his efforts Patrick was unsuccessful and departed while imparting a curse on the King.
According to the Four Masters in the year 726 the death occurred of Congalach of Cnucha.
In 916 the Annals tells us that Niall Glindubh of the Northern Uí Neill became High King of Ireland and is referred to as "Niall of Cnucha" which signifies both the ascent of Cnucha (Castleknock) in prominence as well as the descent of Tara as a royal seat. In September 919, Niall gathered the Irish Chiefs and their armies at Castleknock from where they led a fight against the Danes who had regained their power over Dublin. The Battle of Islandbridge, also known as the Battle of Áth Cliath, proved to be Niall's last battle. He was slain along with five other Irish Chiefs and their armies were subdued.
Feudal period
In 1171, the High King of Ireland, Ruaidrí Ua Conchobair, gathered his forces at Cnucha to counter the Norman invasion of Ireland. Ua Conchobair was comfortable at Cnuch having overcome his Danish vassals in the Kingdom of Dublin some years previously. The siege exerted pressure on the forces of the Cambro-Norman leader, Strongbow, who asked the Archbishop of Dublin, Lawrence O'Toole to negotiate with the High King at Cnucha. Strongbow's offer to recognise Ua Concubhair as High King was rejected. He was commanded to depart from Ireland immediately. Strongbow was furious but Maurice de Prendergast, who had accompanied Archbishop O'Toole, had observed that the Irish troops were largely inactive and unready for battle. His report to Strongbow spurred him to lead a successful attack against the High King's armies. Ua Concubhair fell back from Cnucha and the other Irish Chiefs returned to their territories. The battle was lost and the Norman conquest of Ireland was successful. Following the siege, the Normans realised the strategic importance of the location which looked over the city of Dublin. Consequently in 1177, a feudal barony of Castleknock was created out of the Lordship of Meath by Hugh de Lacy, Lord of Meath who granted it to Hugh Tyrrel. It was held for three and a half knight's fees, owed to the superior Lord of Fingal.
The title and lands of Castleknock were held by the Tyrell family until 1370 when Hugh Tyrell and his wife died of the plague. It passed by inheritance to the Burnell family. The first Baron, Hugh Tyrrel, gave lands in the barony at Kilmainham to the Knights of St. John whose legacy continues in the area today in the form of St. John Ambulance. Later, civil parishes, based on the boundaries of the ecclesiastical parishes of the Established church were used to sub-divide the barony.