In the year 1169, when the first Norman invaders landed in Ireland, the private castle had been in existence in England for more than a hundred years, and had it been suited to the social organisation of the Irish people, there had been plenty of time for its introduction into Ireland. Nor are we in a position to deny that some chieftain with a leaning towards foreign fashions _may_ have built for himself a castle in the Anglo-Norman style; all we can say is that there is not the slightest evidence of such a thing.[1036] We have two contemporary accounts of the Norman settlement in Ireland, the one given by Giraldus in his _Expugnatio Hibernica_, and the Anglo-Norman poem, edited by Mr Goddard H. Orpen, under the title of the "Song of Dermot and the Earl."[1037] Now Giraldus expressly tells us that the Irish did not use castles, but preferred to take refuge in their forests and bogs.[1038] The statement is a remarkable one, since Ireland abounds with defensive works of a very ancient character; are we to suppose that these were only used in the prehistoric period? But if castles of the Norman kind had been in general use in Ireland in the 12th century, we should certainly hear of their having been a serious hindrance to the invaders. The history of the invasion, however, completely confirms the statement of Giraldus; we never once hear of the Irish defending themselves in a castle. When they do stand a siege, it is in a walled town, and a town which has been walled, not by themselves, but by the Danes, to whom Giraldus expressly attributes these walls. Moreover, the repeated insistence of Giraldus on the necessity of systematic incastellation of the whole country[1039] is proof enough that no such incastellation existed. It is true that in some of the earliest Irish literature we hear of the _dun_, _lis_, or _rath_ (the words are interchangeable), which encircled the chieftain's house.