Colgan (Acta. S.S. 8 Jan.) says, “St. Ergnata flourished
about the year of Christ, 460, and our Hagiologists relate,
that her festival was celebrated in the Church of Cluainda-en
(the meadow of the two birds), in the district called
Fiodhbhaidh (Feevagh), and in the Church of Tamhlact-bo,
both on the 8th of January, and on the 31st (recte 30th), of
October.” Colgan adds in a note that Cluain-da-en is a
parochial church on the banks of Lough Neagh. Two
transcripts of the Calendar of Aengus, read at the 30th of
October, where it commemorates St. Ernach — “Ernach a
virgin (uag) a high pillar,” but the oldest transcript which
Whitley Stokes gives, reads, “Ernach, a youth (oc), a high
pillar.” It is obvious that there were two saints, one a
virgin, the daughter of the prince, who gave Armagh to St.
Patrick; she was named Ergnata, or Eargnath, or Herenat,
and was honoured on the 8th of January, with a festival in
the Church of Tamlachtbo, in the parish of Eglish, Armagh. While there was another saint called by nearly
the same name, though a man, who was honoured by a
festival in the Church of Duneane, which was held on the
30th of October. In process of time, the hagiologists confounded the two on account of the similarity of names.
Thus the Calendar of Donegal has, at the 8th of January, “Eargnat, Virgin of Dun-da-en, in Dalaraidhe,” and
again at the 30th of October, it has

“Hercnat, Virgin of Dun-da-en, in Fiodhbhadh (Feevagh),
of Dalaraidh.”

The note on the Festology of Aengus, in the L. Breac,
sets the matter at rest.

Ernach-i-MacTairnd, &c., Ernach, i.e. son of Tairnd, is his
name, but it fitted not the quatrain; and in Dun-da-en, in
Fidbaid (Feevagh), of Dalaraidhe, is he”.  Dun-da-en, the old form of the name Duneane, signifies
“the fort of the two birds,” in allusion to some old legend
a version of which is given below. Feevagh is still the name of
district adjoining Duneane. St. Ernach, whose festival was
held on the 30th of October, in Duneane, seems to be the
same St. Ernin, whose festival was held on the 31st of May, in Cranfield.