The early history of Aileach is "lost in the twylight of fable." It is a pre-historic building, almost as much so as a Pyramid of Egypt. It was used as a stronghold down to the beginning of the twelfth century; but when it was built, or by whom, cannot be said to be known from authentic history, for the many poems that exist about its origin in ancient Gaelic are legendary rather than historic. There may be, and there probably is, a great deal of truth in them, but they cannot be accepted as history. Aileach is a circular, dry-stone fortress with walls nine feet thick. It was levelled down to the ground when Mr Barnard undertook its restoration. The history of its destruction is so strange, so unique, and so Irish, that it must be given. Let the Four Masters tell it. They say, under the year 1101, that "A great army was led by O'Brian, King of Munster, with the men of Munster, Ossory, Meath and Connacht, across Assaroe into Innishowen.... He demolished Grianan Aileach in revenge of Kinncora, which had been razed and demolished by Muircheartach O'Lochlainn some time before. O'Brian commanded his army to carry with them from Aileach to Limerick a stone of the demolished building for every sack of provisions they had. In commemoration of which was said (by some unknown poet)-- "'I never heard of the billeting of grit stones, Though I heard of the billeting of companies, Until the stones of Aileach were billeted On the horses of the King of the West.'" This is the only attempt at anything like humour in all the dreary annals of the Four Masters. Such quiet sarcasm would be a credit to Mark Twain. But if the poet had said "King of the South" instead of "King of the West," although it might not have answered his Gaelic rhyme or assonance quite so well, it would have been more correct, for although Munster is west of Aileach, it is more south than west. It can never be known how high the walls of Aileach had been before they were pulled down by O'Brien, because we don't know how many cavalry he had, or how many stones he carried to Limerick. Never before was an army loaded with such impedimenta; but that the story of the stones of Aileach, or at least, stones similar to them, having been brought to Limerick or its immediate vicinity, there cannot be much doubt, for they were found there.