Ordnance Survey Letters by John O'Donovan and Eugene Curry, 1839

Parish of Killaloe (b)

Immediately to the north of the Cathedral there is a small stone roofed Church or Duirtheach, not unlike Saint Columbkille’s House at Kells or St. Kevin’s Kitchen at Glendalough. It measures on the outside thirty six feet four inches in length and twenty five feet in breadth. The doorway is placed in the west gable, but I could not ascertain its original height as the ground is several feet raised. It is four feet eight inches in width at the point where the arch springs. The height from the present level of the ground to the vertex of the arch is six feet. This doorway is semicircular at the top and consists of four concentric circles, not unlike the doorway of the Church of Rahen in the King’s County, of Incha Goill in Lough Corrib, and of Saint Caimin’s Church on Inis Cealtra. In the very sharp gable over this doorway is placed, near the top, a round-headed window which afforded light to their upper storey. The roof is of stone, and seems to have been very firmly constructed, but it is now much broken and overgrown with grass and small ash trees.

The little choir of this Duirtheach is now destroyed, but its breadth can be ascertained from stones projecting from the east gable. The choir arch is not unlike in form that in Saint Kevin’s Kitchen, but not so high, being only eight feet six inches high from the present level of the ground. Over the little choir arch near the top of the gable is placed a rectilineally pointed window. We learn from a fragment of the Brehon Laws found in the Manuscript Library of Trinity College, H. 3, 17, p. 653 that every Irish ecclesiastical establishment has its Round Tower, Cathedral and Duirtheach or Penitentiary. In this fragment the usual measurements of the Duirtheachs are given and the prices paid, according to law, for the erection of the Round Towers, Cathedrals and Duirtheachs laid down.

In Cloictheach: a ichtursidhe do thomus; a thomhus sídhe re hichtur in Daimhliag re n-a chutrumaidhe, agus in imarcraidh atá ar a fat agus ar a leithed in Daimhliag ó sin imach o chomhthomus in chloctíghe imach is a riaguilside re airde in cloctíghe; agus da raibh imarcraid air i.e., ar áirde in cloctíghe risin damliag is comór log ris in cutruma loigidachda sin do thabhairt ar in clocteach.
The Cloctheach: let its base be measured; let it be proportioned to the base of the Damhliag, and the surplus of the length and breadth of the Damliag over the dimensions of the tower, is the rule to determine the height of the tower. And should the height of the tower exceed the dimensions of the Damliag, its price is to be raised accordingly.

Until this passage was discovered the history of the Round Towers of Ireland was envolved in obscurity notwithstanding all the gropers who had attempted the enquiry, but this and other passages preceding and following it throw a flood of meridian light upon their dates and use. I should be glad to hear your opinion as that of a professional measurer on the manner in which you think they proportioned the base of the tower to that of the Cathedral. I have tried it every way but I could not come to anything like certainty. My surmises are written; be so good as to let me hear your more judicious and more experienced opinion. I have not yet met any Damliag near any Round Tower that has not been remodelled and enlarged but the usual length was sixty feet and the breadth from twenty one to twenty four.

The usual dimensions of the Duirtheachs according to this tract were fifteen feet in length and the breadth ten feet; but this Dairtheach belonged to a very distinguished Church and seems to have been erected at a period when the Irish Church had attained to some degree of splendor.

This little building is traditionally called Old Killaloe and said to be the house in which Brian Boroo’s workmen deposited their implements when they were building the Cathedral. For a description of another old Church on an island in the Shannon near Killaloe see Grose and my letter on the Parish of Templechally on the other side of the Shannon in Tipperary.