tir cumaile [Old Irish]

In Ireland, 7th? – 12th centuries?, a unit of land area, probably on the order of 13.87 hectares (34.27 acres).

“Tir” means “land.” “Cumaile” refers to three milk cows. Some have described the tir cumaile as the amount of land needed to pasture three milk cows. However, in a climate like Ireland's, 13 hectares is much more land than three cows need. Currently pasture is a larger part of the diet of dairy cows in Ireland than in any other European country; even so they commonly stock 2.5 cows per hectare, with as little as 80 kg of supplemental feed per year1!  The eDIL2 describes one sense of cumal as “Name of a variable unit of value; generally fixed at three milch cows”, and the tir cumaile is probably the amount of land that was at some point worth three milk cows.

The surviving Brehon Laws contain two passages that purport to describe the size of the tir cumaile:

.i. tri graindi i norlach, ceithri orlaighi i mbais, teora basa i troghid, da troigid dec i fertaig, da fertaigh dec i forraigh, da forraig dec i tir cumaile dia fot, se foirrge dia lethet, ma beith ina toimsib techtaib. 

That is, three grains are in an ordlach, four ordlach in a bas, three bas in a troigid, twelve troigid in a fertaig, twelve fertaig in a forrach, twelve forrach in a tir cumaile, 6 forrach in its breadth, if it be of lawful dimensions.

Commissioners for Publishing the Ancient Laws and Institutes of Ireland.
Ancient Laws of Ireland. Volume III.
Senchus mor (conclusion) being the Corus Bescna, or Customary Law, and the Book of Aicill.

Dublin: Alexander Thom, 1873.
Pages 334-337. From the Book of Aicill.

 cesc — Cotoimsib tir cumaile? A grainni : tri grainne i nordlach innraic; se ordlaige i ndorn; ocur da dorn a traigid; se traigthi i ndeisceim ; se deisceimeanda a ninntrit; se inntrit a lait; se laiti a forraig; se forraig i nairceand. Tir cumaile da forraig .x. dia fot.

Question— How is a tir cumaile measured? By grains: three grains in a proper ordlach; six ordlach in a dorn, and two dorn in a troigid, six troigid in a deisceim; six deisceim in an inntrit, six intritts in a lait, six laits in a forrach, six forrachs is its breadth. A tir cumaile is twelve forrachs in length.

Commissioners for Publishing the Ancient Laws and Institutes of Ireland.
Ancient Laws of Ireland. Volume IV.
Din Techtugad and Certain Other Selected Brehon Law Tracts.

Dublin: Alexander Thom & Co., 1879.
Page 276.

Let us chart the relationships the passages describe. We will let 1 ordlach = 1 inch, which is close if not strictly accurate, and will give us some idea of the magnitudes of these units.

forrach

fertaig

12

trogid

12

144

bas

3

36

432

ordlach

4

12

144

1728

grain

3

12

144

1728

20736

1 in

4 in

1 ft

12 ft

48 yd

forrach

lait

6

inntrit

6

36

deisceim

6

36

216

trogid

6

36

216

1296

dorn

2

12

72

432

2592

ordlach

6

12

72

432

2592

15552

grain

3

18

36

216

1296

7776

46656

1 in

6 in

1 ft

6 ft

12 yd

72 yd

432 yd

 

The passages agree that the tir cumaile is (6 forrachs × 12 forrachs =) 72 square forrachs. The forrach in the latter passage, however, is 9 times bigger, resulting in a tir cumaile that is 81 times bigger — about 1124 hectares (about 2776 acres), which is beyond belief. The scribe or copyist has made an error of some sort. The two passages would agree if any two of the 6's were actually 2's, i.e., if there were 2 deisceims in an intritt and 2 intritts in a lait, or if there were 2 intritts in a lait and 2 laits in a forrach, or (my own guess, preserving the symmetry) 2 deisceims in an intritt and 2 laits in a forrach. Unfortunately, though we can check (roughly) the sizes of all the smaller units from other meanings of the words (e.g. dorn - fist; troigid - foot; deisceim - double step, or pace), the quoted passage is the only known occurrence of the word inntritt, and the only occurrence of lait as a unit. Hopefully more instances of inntrit and lait will turn up and reveal the meanings of these words, but it is unlikely to make much change in the magnitude of the tir cumaile.

1. Myles Rath.
"Positioning Your Dairy Farm Business for a Profitable Future- A European Union Perspective."
Faculty of Agriculture, University College, Dublin.

2. The eDIL may be accessed at www.dil.ie. The quotation was accessed 29 August 2008.

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