Here we meet three Irishmen from the mistical days of early Irish history: first Lulaig of the Ligmuini tribe, and then Gede Ollgothach and Ollfhinnachta.
1) The Ligmuini are an utterly obscure but perhaps once at least moderately powerful tribe from the period 400-600 AD when Ireland was still half-legendary. The tribe was located maybe in Westmeath and one of their kings was said to be Dairbre mac Lulaig.
Dairbre’s name is similar to another name common to this time — Cairbre. Corruption of same name? Or do the similar names indicate some sort of cultural connection? ‘Dairbre’ would indicate a connection with the ‘oak’ (cf the deity Daire and the Darini tribe for example). Cairbre might be linked to corb ‘crow’ or car- (‘dear’ or ‘beloved’ and a common name element). As this period is around about time of Cairbre Cattchenn (‘cat head’, FOLK ETYMOLOGY BEWARE!), perhaps Dairbre and Cairbre ‘Cat-Head’ are in fact related figures?
Anyway, around the time of the real not shakespeareplayian MacBeth there was a Lulaig in Scotland (whose byname was ‘the foolish’). This is interesting because that name seems obviously comparable to the Pictish name Lutrin. Long ago Kenneth Jackson satisfactorily explained ‘Lutrin’ as deriving from *Lugutrenos: ‘strength of the god Lug’. Given that, we can likewise derive the first element of Lulaig from ‘Lug’ (or ‘Lu’ in Pictish). The second element could then be explained by reference for example to the name ‘Lagin’ (laig, ‘spear men’). Lulaig then would mean ‘spear of Lug’, effectively a synonym for ‘Lutrin’.
So is Lulaig a ‘Pictish’ (ie northern British) name and therefore were the Ligmuini a northern British people intruded into Ireland, perhaps as allies of the Scotti? Or otherwise related to northern Britain?
II) Other equally obscure characters abound from around the same period. So for example the Irish World Chronicle tells us :
Secht rig di Chruthentuathaib rofollnaisset for Herind co tanic Cond Cetchathach.
Which tells us that seven ‘British’ (Cruthin) kings were High Kings of Ireland. The Lebor Gabala (‘Book of Invasions’) mentions Gede Ollgothach and Ollfhinnachta as two among these.
Note the ‘Oll’. In Gaelic this would imply ‘great’, for what that is worth, which might be a lot if we consider the evidence from Britain. For there, we are told, the defender against the English was not just a leader ‘tigern’ but a great leader ‘vor tigern’ > Vortigern. Perhaps here we have a comparable ‘Gede the Great Gothach’ and a ‘Great Finnacht’.
Our core names, at any rate, seem to resolve into Gede Gothach and Fhinnachta.
The latter seems easy enough to explain. It means ‘warband’. Galatai, Gaesatai, fiannacht. And Gede? Here we might consider one of the British names for the invaders from o’er the Irish sea. The Goidels. So, here maybe goid and gede and goid and goth are equivalent.
The connection between the Scotti and the Feni and the Goidel is to my mind a given. So, whoever they in fact were, I think that by their very names Gede Ollgothach and Ollfhinnachta link them most strongly to the period when Irish warbands were attacking Roman Britain and Roman Britain was seeking ways to defend itself.
Perhaps Gede and Goth can be related to the Welsh ‘gwydd’ (wild, gwyddel ‘wildmen’) behind the name Goid-el and perhaps ‘finnechta’ is a reference to the Feni (synonym for ‘Goidel’).
I suggest, to conclude, that Lulaig, Gede Ollgothach and Ollfhinnachta belong to the same cultural context as the better-known figures of the period of Irish raids on Britain and of the consequent Roman and port-Roman ‘blowback’ and that this in term may provide the context for the existence of the name ‘Cruthin’ in Ireland.