The 7thC Patrician biographer Tírechán is a valuable source for some details of the Atlantic religion in Ireland. His work – known as the Collecteana occurs in the Book of Armagh – MS52 of Trinity College Dublin. One of the mysterious Irish words he left in his Latin hagiography of the saint is the word 'erdathe' which Tírechán claims was the term used by Irish pagans for their equivalent to the 'day of reckoning of the Lord'. It can be found in the last paragraph of Folio 10r…

12 (1) Perrexitque ad ciuitatem Temro ad Logairium filium Neill iterum, quia apud illum foedus pepigit, ut non occideretur in regno illius; sed non potuit credere, dicens:(2) “nam Neel pater meus non siniuit mihi credere, sed ut sepeliar in cacuminibus Temro quasi uiris consistentibus in bello” (quia utuntur gentiles in sepulcris armati prumptis armis) “facie ad faciem usque ad diem erdathe” (apud magos, id est iudicii diem Domini) “ego filius Neill et filius Dúnlinge Immaistin in campo Liphi pro duritate odiui ut est hoc”.12 (1) And he proceeded again to the city of Tara to Loíguire son of Níall, because he made a pact with him that he should not be killed within his realm; but (Loíguire) could not accept the faith, saying:(2) 'My father Níall did not allow me to accept the faith, but bade me to be buried on the ridges of Tara, I son of Níall and the sons of Dúnlang in Maistiu in Mag Liphi, face to face (with each other) in the manner of men at war' (for the pagans, armed in their tombs, have their weapons ready) until the day of erdathe (as the magi call it, that is, the day of the Lord's judgement), because of such fierceness of our (mutual) hatred.'

So… what is erdathe? There are two problems in determining the answer to this question: Firstly, is this really the word in the original text (written in 9thC insular minuscule text)? Secondly, the lack in standards for orthography from such early written Irish would make the word (whatever it is) a difficult one to find a more modern equivalent for…

Let's take a look at the first problem. Here is a facsimile of the word as written in paragraph 12 (Folio 10r) of the actual manuscript:

For those not accustomed to 9thC insular miniscule scripts, the initial e or a and the following r are compound or ligated and the 'r' part shows the typical dependant leg of the 'long r'. Third letter is 'd', fourth 'a', fifth 't' (capitalised in style), sixth 'h' and final a definite 'e': a/e-r-d-a-t-h-e. So: this is definitely the correct word, but the first letter might be an 'a'. You might also note the four dots above the d, a, t and 'e' where the scribe rested his nib while considering how to write the Irish word – one he was unfamiliar with and which has no other attestations in this form of spelling. This hesitancy on his part might also have given the indeterminate a/e at the start of the word. This leaves us to examine the second problem – that of meaning:

In addressing the second problem, it is necessary to take a phonetic approach and cast a wide net to see how this word relates to later Gaelic words:

Irish:

The words ard and ath(e) appear to compound the word ardathe/erdathe. This offers us a straightforward translation, for 'ard' = 'height', 'high' or 'elevated'. However, the 'athe' part (-ath is not a usual suffix in the Irish language) is slightly more problematic, unless of course it is a pure compound word, in which case áth, meaning a 'ford' or an 'open space or hollow between two objects' (eDIL) seems a likely offering. The áth is a typical place for combats to occur in narrative tales such as those of the Ulster Cycle, and in particular the Táin Bó Cúailnge… this implies a liminal place where 'crossing-over' (death) might occur, as well as being a place typical for the territorial combats of rutting stags on river plains etc. It therefore shows a link of sorts to the word cath- which suffixes terms to do with battle or defence (e.g. Conn Cétchathach – Conn of the Hundred Battles); Bear in mind that the 'd' of 'erd' or 'ard' would possibly lenit a following hard consonant to give '-ath'. Other words that would fit this schema might include 'rath' and 'math'. The use of ath- as a prefix also implies an act of repetition. 'Athair' of course means 'father' – a term used to mean 'god' by Christians ('Pater noster…')

Manx: (definitions from Juan Kelly's Dictionary – Manx Society Vol.13)

The Manx language is a treasure trove for those looking for more ancient forms of Irish, having remained in a purely spoken form until the 17th century, and having enjoyed a level of cultural stability that Ireland could not, and which in turn preserved many aspects of Atlantic religious folklore that was otherwise lost. Literature has a habit of informing the 'correct' pronunciation and flow of ideas in a culture… The best guess of 'erdathe' in Manx is seen in the two forms of the expression for 'high', 'elevated' or 'exalted' – based on the rootword ard:

“Ardaght, ardys, s. height, eminence” – the round 'a' takes on a hollow 'e' sound to make the adjectival:

“Yrjey, a. high, eminent; also promoted, advanced.” – the Manx terminal -ey is pronounced '-ya' or '-yu'. The equivalent of 'ardaght' would by 'yrjaght'. In fact 'erdathe' might be pronounced in exactly this fashion with flat vowels: “er-jer-he”! These are effectively Anglophone ways of writing Irish words, after all…

Sanas Chormaic (Cormac's Glossary):

Another more intriguing and perhaps more likely possibility is a word given by the famous Cormac of Cashel in his 'glossary' of the 10thC. This word (from page 5) is Audacht which Cormac translates as