Erc (d. 513/15), bishop of Slane and saint in the Irish tradition, belonged to the obscure Munster population-group of Corco Auloimm. His father is named in the genealogies as Daig son of Branchú, and he shares his Corco Auloimm ancestry with St Brendan (qv) of Birr. According to the hagiographers, a bishop named Erc was magister (tutor) to St Brendan (qv) of Clonfert. There may be confusion here – an assumption having been made that the latter was related to Erc – or it may simply be coincidence. Magister Erc is stated in the Lismore Life of Brendan of Clonfert to have belonged to the Ciarraige; in any event, as the Brendan in question lived till 578, it seems unlikely that he could have studied under the bishop of Slane.
Erc of Slane belonged to the first generation of the native Irish church. Patrician hagiography represents him as a convert; he is said to have been a jurist, and is placed along with the poet Dubthach (qv) of the moccu Lugair and his pupil Fiacc (qv), later bishop of Sletty, at the court of King Lóegaire (qv) on the occasion of the alleged visit of St Patrick (qv) to Tara. By the time the earliest Lives of Patrick came to be written in the seventh century, Erc was already regarded as the judge in Patrick's retinue, which probably represents a desire to associate the practice of law and other professions with the early church. He is said to have been blessed by Patrick at the ecclesiastical site of Ferta Fer Féicc near Slane; he seems to have spent his episcopal career in the Slane region. At least according to later tradition, he was (or had been) married and was the father of Éogan (qv) (fl. c.570), subsequently bishop of Ardstraw.
Erc is commemorated in the martyrologies at 2 November, which is probably the date of his death; the year is variously given in the annals as 513 or 515. His alleged age of 90 at the time of death doubtless reflects efforts to synchronise his floruit with a Patrician mission that was understood to have commenced in 432. The relics of Bishop Erc were brought on circuit in the east Meath region at a time of famine and disease in 776.