From Thomas Walsh's History of the Irish Hierarchy:
"St Asicus is mentioned as the first bishop of Elphin and to have been placed in the see by St Patrick but it is doubtful whether he has been one in the lifetime of the apostle. The festival of St. Asicus is celebrated on the 27th of April but the year of his death like unto the deaths of other saints is not known. Ware fixes his incumbency in or about 450. It is said that Asicus was an excellent goldsmith and that he adorned the cathedral with monuments of elegant workmanship that he also wrought for St. Patrick quadrangular chalices and altars. It is also related of him that through a penitential spirit he retired from his diocese to the mountain Slievliag in Donegal where, after sojourning a considerable time, he was discovered by his disciples. He could not be induced to return to his see but went with them to a solitude and when he died was buried at Rathcunga barony of Tyrhugh in that county. Next to Asicus is mentioned his nephew Bitheus bishop of Elphin and who was buried with Asicus in Rathcunga. Bron bishop of Caisseal Iorra was the contemporary of both and died in the time of St. Bridget, AD 512. The names of the successors are lost to our enquiries but may we not hope that they are recorded in the book of life."
"Rathcunga in the barony of Tir Hugh. A very old establishment St Asicus of Elphin and Baithen are interred here St Patrick is said to have erected this church."
"881 Asicus bishop of Elphin Biteus and Tassach who fabricated sacred utensils are noticed as such as well as Dageus The ingenuity of the last saint is described in his life which Colgan quotes Idem enim episcopus Dageus abbatibus aliisqne Hibernite Sanctis campanas cymbala baculos cruces scrinia capsas pixides calics discos altariola chrismalia librorumque coopertoria qusedam horum nuda quaedam vero alia auro atque argento gemmisque pretiosis circumtecta pro amore Dei et sanctorum honore sine ullo terreno pretio ingeniose ac mirabiliter composuit."
"See of Rathcunga county of Donegal: St Bitheus. was the founder was contemporary with Bron of Cashel Iorra and Asicus of Elphin, who was his uncle. It is likely that he was also bishop of West Cashel. He has been buried at Rathcunga where the remains of his uncle St Asicus were deposited."