residence in "the green mounds, known by the name of _Sídh_," that they
were called "the _Fir Sídhe_ [_i.e._, men of the _sídhs_], or Fairies,
of Ireland."[82] The one word, indeed (_sídh_), became indifferently
applied to the dwellings and the dwellers. Whichever was the earliest
meaning of that word, there is little dubiety as to the etymology of
_Siabhra_. In one copy of the _Leabhar na h-Uidhre_,[83] it is stated
that the Tuatha De Danann "were called _Siabhras_." O'Reilly defines
_siabhra_ as "a fairy," and _siabhrach_ as "fairy-like"; while "a fairy
mansion" is _siabhrugh_. With Connellan, again, _siabhrog_ is "a fairy."
It seems quite evident that these are all corruptions of _sídh-bhrugh_
(otherwise _Sídh an Bhrogha_, as above), and that _Siabhra_, as applied
to the _dwellers_, was simply a transference from the name denoting
their _dwellings_.

Numerous as are the references to this mound as a "dwelling-place," its
name figures prominently in the list of the ancient cemeteries of
Ireland. _Relec in Broga_, "the Cemetery of the Brugh," is referred to
as one of "the three cemeteries of Idolaters," in an Irish manuscript of
the twelfth century (or earlier), the _Leabhar na h-Uidhre_ cited above.
Of the two others, one is "the Cemetery of Cruachan"; and, by glancing
at it, in the first place, we shall obtain a good idea of the Cemetery
of the Brugh. "We find that the monuments within the cemetery at
Rathcroghan,"[84] says Mr. Petrie, "are small circular mounds, which,
when examined, are found to cover rude, sepulchral chambers formed of
stone, without cement of any kind, and containing unburned bones."[85]
And the twelfth-century scribe whom Mr. Petrie largely quotes, says that
there were fifty such mounds (_cnoc_) in the cemetery at Cruachan. This
mediæval scholar has copied a poem on the subject, "ascribed to Dorban,
a poet of West Connaught," wherein it is said that it is not in the
power of poets or of sages to reckon the number of heroes under the