The Pre-Christian Era

        Long before the castle was built, however, the hill upon which it stood was well known in Irish history under the name of Cnucha. It is mentioned several times in the Annals of the Four Masters, Keating's History of Ireland, and in several of the older Annals, both in reference to pre-Christian times and the earlier ages of Christianity. Here we are told, during the Milesain era, Conmhael of the race of Ebher defeated the descendants of Eremhon, and later, it is described as the dumha of the sons of Eremhon, implying that it was a place of note and used as a residence. Conn of the Hundred Battles dwelt there, Felim son of Conn is described as the brave King of Cnucha and a famous battle was fought here in the second century. All these events are recounted more than once by the early Irish writers and an account is given of the origin of the name.
        Castleknock, or its Irish equivalent, Caislean, is a name of comparatively recent origin. The word Castle, of course, does not appear until Norman times. In documents relating to the twelfth and thirteenth centuries the place is called Castrum Cnuc, or simply Cnuc. Norman-French writers used the expression Chastel-cnoc or Castel-cnoc. The earliest Irish names seem to mean the "Druid's Mound" or grave; it was also called "Cnock Bran", probably from the name of the druid buried there. But the best known name, and the one by which it is always called in later Irish Annals, is Cnucha. It seems almost obvious that this name is derived from the Irish word Cnoc - a hill, and that the reference is to the position of the ancient residence or mound.
        The site in ancient times must naturally have attracted attention. On the south side the land slopes down to the banks of the Liffey in a direct line, the river being only between five and six hundred yards distant, hence, Cnucha is described as "over-hanging the Liffey." Ancient Irish writers are, however, unanomous in deriving the name not from the site, but from a person called Cuncha or Cnucha. They do not, however, agree in their identification of this person. Some state she was one of the earliest settlers; others that she was the foster-mother of Conn of the Hundred Battles. Both versions are found in prose and verse in the Ding Senchus:

        Cnucha a hill above the Liffey,
        There was a time when it was a kingly seat,
        It was a house for guests once on a time
        When Tuathal the Rightful owned it.

        Tuathal, in the beginning, built it,
        It was the fortress of kings, a royal work;
        There was only Tara was a better dwelling
        That was more beloved by the King of Eire.

        The foster-mother of Conn, who loved strife,
        Was Cnucha of the beautiful head,
        She dwelt in the painted fortress
        In the days of Conn of the Hundred Fights.

        The woman was buried, sorrowful it was,
        In the centre of the hill,
        Son that Cnucha from that time forth,
        Is its name till the day of judgement.

        Where was fought the sharp battle,
        On the spot where stand two cairns,
        There met in combat the hosts
        By whom was slain Cumhal son Trenmhor.

Though several battles were fought in the neighbourhood in early times, the best known is that referred to above. It is described in more then one of our oldest MSS., and frequently mentioned in the literature of the Fianna na h-Eireann. The Annals of the Four Masters date this battle under A.D 190. Accounts do not agree in assigning the causes of the battle; but all relate the chief event of the day - the death of Cumhal, leader of the Fianna of Leinster, by the hand of Goll Mac Morna, leader of the men of Connacht. Although we have no direct evidence that Cumhal was buried on the spot where he fell, still there seems to be sufficient foundation for the tradition that the mound inside the College entrance is his tumulus.

Castleknock College,
Dublin 15,