The name of today's saint, Eargnat, appears under a number of variations in the sources. The entry in the Martyrology of St Oengus for January 8 records :
The death of Ecimon,
A bishop chaste and noble,
Ercnat chosen to the inheritance
Nectan the noble of Alba.
while the Martyrology of Donegal reads:
8. A. SEXTO IDUS JANUARII. 8.
EARGNAT, Virgin, of Dun-da-en in Dal-Araidhe.
Canon O'Hanlon places our saint within the hagiography of Saint Patrick:
From the Irish Apostle's Lives, it would seem, that Ercnata was the daughter of Darius, and that she flourished as a contemporary of St. Patrick. .. Among the noble ladies, who received the veil from St. Patrick, St. Ercnata or Ergnata is enumerated.
I followed up the references in the Tripartite Life of Saint Patrick. First, the name of 'Erc, daughter of Dare' appears in the List of Saint Patrick's Household as one of three 'embroideresses'. The second reference to this holy needlewoman was even more striking and involves another member of the Patrician household, Benen the Psalmist:
Dare's daughter loved Benen. Sweet to her seemed his voice at the chanting. A disease came upon her, and thereof she died. Benen took relics to her from Patrick, and straightway that holy virgin rose up alive, and afterwards she loved him spiritually. She is Ercnat, Dare's daughter, who is in Tamlachta Bo.
The Martyrology of Donegal records this incident as well, in the entry for the feast of Saint Benen on November 9:
The holy Benen was benign, was devout ; he was a virgin without ever defiling his virginity ; for when he was psalm-singer at Ard-Macha along with his master, St. Patrick, Earcnat, daughter of Daire, loved him, and she was seized with a disease, so that she died suddenly; and Benen brought consecrated water to her from Patrick, and he shook it upon her, and she arose alive and well, and she loved him spiritually afterwards, and she subsequently went to Patrick and confessed all her sins to him, and she offered her virginity afterwards to God, so that she went to heaven ; and the name of God, of Patrick, and of Benen, was magnified through it.
Ultimately, Eargnat is rescued from the death of both body and soul, since spiritual love triumphs over carnal passion as our saint finds redemption by devoting herself to her Heavenly Bridegroom. It's a poignant tale but also a moral one. And for a Victorian Catholic writer like Canon O'Hanlon, the moral of the story was the danger that even the most innocent friendships and pleasures can be twisted into 'occasions for sin'.
O'Hanlon also identifies two possible feast days for our saint:
Our hagiographers assign two different festivals to honour her. One of these occurred on the 8th of January, and the other on the 30th of October. The first denotes the day of her natalis; the other feast probably marks some particular event during her life, or a translation of her relics after death.
This holy penitent's acts have been written by Colgan. See Acta Sanctorum Hiberniae, viii.Januarii. Vita S. Ergnata, pp. 41, 42. Colgan mistakes, however, in assigning Dun-da-en to the diocese and county of Down. Her place is now called Duneane, in the county of Antrim. There is a St. Herenat, Virgin, of this same locality, entered at the 30th of October. It appears most probable, they are identical; in which case, this virgin had a double festival in the year.
If the Co. Antrim saint is the same person as the daughter of Dare, a land-holding chieftain in the Armagh area, I am wondering how to account for her identification with these two different places. I hope that perhaps more recent research might provide an answer.