Battlefield in Castleknock (without Phoenix Park)

Battle of Castleknock, 1171 - summary by Dr Gavin Hughes. Uploaded 22/02/2021 Olive Alcock The battle of Castleknock was one of three battles fought in Dublin between 1170 and 1171 (see also the battles of Dublin (DU018-020438-) and Hoggen Green (DU017-098----)). All three were integral engagements connected with the Anglo-Norman conquest and provincial/national struggles for dominance. While it is very likely that Castleknock was the last one fought, it was possibly intended to take place contemporaneously with the Viking landing which resulted in the battle of Hoggen Green. As with that battle, the sources for the engagement are entries in the Song of Dermot and the Earl (Mullally 2002, 97-8), Giraldus Cambrensis' Expugnatio Hibernica (Scott and Martin 1978, 74-5, 78-9, 8 2-3, 306) and the Annals of Tigernach (Stokes 1895-7, vol. 2, 428). The dating of this battle is problematic but the sources all suggest that Ruaidrí Ua Conchobair, high king of Ireland, raised his Connacht army having heard the news of the death of Diarmait Mac Murchada, king of Leinster. This, according to Cambrensis (Scott and Martin 1978, 74-5), happened in May and both Anglo-Norman accounts (ibid. 78-9; Mullally 2002, 97) state that the battle was preceded by a two-month long siege. It is thought that it must have taken at least a month for Ua Conchobair to muster his forces and march them to Dublin, so it is assumed that the earliest date of his arrival was June. As such, it is probable that the battle occurred sometime around August, although late July or early September are also plausible. All of the three main sources agree that the Anglo-Norman garrison was commanded by Richard de Clare (Strongbow), earl of Pembroke, accompanied by Myles de Cogan and Raymond Le Gros. Cambrensis (Scott and Martin 1978, 74-5) is the only source to mention Maurice FitzGerald as being present, whilst the Song (Mullally 2002, 97) alone records the presence of de Clare's remaining Irish allies - Domnall Cáemánach, Amlaib Ua Garbith and Ua Ragallaig of Tír Brúin. The size of the earl's army was split into three fighting companies, which comprised either 90 knights, according to Cambrensis (Scott and Martin 1978, 82-3), or 120 knights, according to the Song (Mullally 2002, 98), all of whom were mounted. These were further supported by archers and foot soldiers. It appears that, as at the battle of Dublin in 1170, de Clare was in the 3rd company with his Irish allies and it seems as if his overall army strength stood at less than 1,000 men. Against this force, Ua Conchobair, as high king, raised contingents from the provinces and had the support of many Gaelic kings and lords, although the Annals of Tigernach (Stokes vol. 2, 1895-7, 428 disagree on who was actually present at Castleknock. However, all the sources agree that Tigernán Ua Ruairc was involved and it seems very possible that Muirchertach, Diarmait Mac Murchada's brother, and Murchad Ua Cerbaill of Airgíalla were there. Other lords thought to have been present were more surprising, such as Mac Duinn Shléibe of the Ulaid and Ua Brian, king of Munster. Equally, Guthred of the Isle of Man supplied around 30 ships (whether these were linked to Askulv's forces employed at Hoggen Green is unknown) that sailed into the river Liffey and blockaded Dublin port. Just as it is difficult to identify which individuals were present at the battle, accounts do not agree on the size of Ua Conchobair's force but, clearly the sheer size of his army took the Anglo-Normans by surprise. The Song (Mullally 2002, 98) claimed his army was 60,000 strong, whilst Cambrensis (Scott and Martin 1978, 82-3) stated it was half this number. It is now believed to probably have been around 3,000 men. All the accounts suggest that Ua Conchobair besieged Dublin through a process of encirclement by a series of camps; Mac Duinn Shléibe was stationed at Clontarf, Ua Brian was based at Kilmainham, Muirchertach was at Dalkey and Ua Conchobair established himself at Castleknock. It seems that the siege and blockade began to have the desired effect upon the defenders of Dublin, with food noted as becoming scarce. This may have prompted de Clare's attempt to negotiate with Ua Conchobair, although these talks allegedly broke down when Ua Conchobair informed de Clare that the Anglo-Normans would only be allowed to keep the former Hiberno-Scandinavian towns (Dublin, Waterford and Wexford). As such, it is thought that de Clare, supported by FitzGerald and le Gros, decided to strike quickly at Ua Conchobair’s main siege camp at Castleknock. Given the confusion surrounding the date of the battle, the accounts are remarkably precise regarding the timings of events on the day itself. The Anglo-Normans mustered out of Dublin at around 4pm (or slightly earlier), deliberately intent on catching Ua Conchobair's forces off-guard. A sortie 'en masse' was effected, heading out for Finglas but arching back east upon Castleknock, possibly using the Tolka valley as cover and taking the camp there by complete surprise. Both the Song (Mullally 2002, 98) and Cambrensis (Scott and Martin 1978, 82-3) refer to the Irish bathing (and Ua Conchobair who 'chanced to be sitting in his bath') when they were attacked. Although the Annals of Tigernach (Stokes 1895-7, vol. 2, 428) clearly state that when the attack happened, Ua Conchobair and his cavalry were elsewhere. Furthermore, it strongly suggests that the subsequent massacre was only of the 'rabble' (da ndaescursluagh) and associated camp followers. However, if this was the case, it does not explain the complete disintegration of Ua Conchobair's siege camps surrounding the city or their immediate withdrawal. Indeed, the result was a complete victory for de Clare and a humiliating rout for Ua Conchobair. Cambrensis’ (Scott and Martin 1978, 82-3) comments that de Clare's triumphant force followed the fleeing Connacht men until the evening, returning to Dublin with much plunder. As such, it is very possible that the battlefield stretched over some considerable distance. Again, the accounts give variable casualty figures, with the highest number being 1,500 of Ua Conchobair's army slain. The battle did not see an end to Ua Conchobair's power, but it did end all threats to Anglo-Norman control over Dublin (until the Bruce Campaign in the early 14th century). After Castleknock, any Irish hopes of expelling or extinguishing the Anglo-Norman influence in Ireland quickly evaporated.