Fiachrae is an Irish figure from the days of the Roman Empire’s twilight zone. Even if we do not trust the exact chronologies, he likely lived before Niall of the Nine Hostages. He is said to be son of Eochaid Mugmedon and therefore (say the slippery genealogists) a half-brother of Niall. Fiachrae himself was father of the high-king Nath-I and, along with Brion and Aillil, was one of the three ancestors of the Connachta who ruled the province named after them.
Important guy, then.
It strikes me that the name is strikingly similar to the Latin title vicarius, a key term in the governance of Britain at the time Fiachrae is said to have flourished. This is not a silly kling-klang etymology. The context into which Fiachrae is placed is full of connections to Britain, especially to the north.
As Britannia (and the Empire in general) found itself increasingly under attack, the admins acted. Now the island (the parts under Roman control) was divided into four diosceses. Each of these was governed by a Praefectus (‘boss’) under whom was the Vicarius (‘deputy’).
Of course, Fiachrae was never the deputy of a dioscese, but an important figure for Britain in the period around 370-380 is the general Count Theodosius. It is plausible that the very early genealogies of the northern British reflect the actions of Theodosius in replacing local leaders with Roman-appointed ones such as Quintilius Clemens and Paternus map Tacitus. Ammianus Marcellinus reports Theodosius doing this in Africa during 371, where he replaced local leaders there with praefecti. Just up the road in Hippo, St Augustine confirms that prefects now ruled in place of kings.
In other words, if these lower-level praefecti had a deputy (vicarius), the context for Fiachrae is now considerably stronger.
That such a title survived as a name should be no surprise. The northern Welsh traditions have men named Gwawl (‘wall’, that is Hadrian’s Wall) and Triphun (‘tribune’). In my view the great ancestor of the Gael, Mil Espaine (‘Spanish soldier’), is none other than Magnus Maximus, active in Britain ten or so years after Count Theodosius and who claimed the title of Emperor. Magnus is the Macsen Wledig (‘leader, king’) of Welsh texts. I think also it is at least plausible that the Goidelglais so closely associated with Mil (the Gael < Goidel are named after him) has a disguised Roman name meaning ‘the Irish cohort’ (< Gwyddel [but Latinised?] classis).
Over in Ireland at this (approximate and legendary) time, we have Tuathal Techtmar, whose very name is possibly British (Tudwal, ‘leader of the people’) and his son Fiacha Finnolaid (?< Vindolanda). Niall of the Nine Hostages has plentiful connections to Albu. His mother Cairenn has a possibly Romano-British name (< Carina). Nath I son of Fiachrae ‘died in the Alps’ (ie Albu, or northern Britain).
The actual historical context of Britain (not the legendary context of Ireland), although the information about it is hardly expansive, points clearly to major attacks on the island from the direction of Ireland, and we know that the Romans attempted to deal with the situation by both military and political means. The relationship between the Irish and the Romans was a complex one and sweet deals were no doubt a part of it on both sides. It is for this reason it is hardly unthinkable that a ‘vicarius’ might end up as a figure in Irish legend. If Fiachrae was such a figure, his job would have been to pacify and control the natives (or fellow natives) and clearly his operational base was what was to become Connacht.
It is unlikely Connacht was known by that name in Fiachrae’s time. A plausible interpretation of the scanty evidence says that the Nagnatae, a tribe mentioned by Ptolemy and therefore dating to a time centuries earlier than Fiachrae, may have been the dominant tribe (or tribal group) there. These may be the later Fir Ol Nechmacht or simply Necmacht. As this name looks suspiciously like it has been modelled on the well-known form of Connacht, its original form may have been *Necmat, which in turn would likely go back to *Nagnat and hence the Ptolemaic tribe.
It is in this region we find a curious counterpart to Níall Noígíallach (Niall of the Nine Hostages): Nia Noi nGrainne, known in Latinised form as Nia Novem Generum (Nia of the Nine Seeds, probably ‘peoples’). This may provide the key to the meaning of name Nagnatae, for gnat means ‘offspring’ and joined with ‘na’ we get something close to a *Noignatae (‘nine peoples’).
Which I mention here because, given the above, who would not observe how the name Nath I (son of Fiachrae) is an almost perfect fit: noi + gnatae [?= nath-i].
So, in this interpretation of the almost non-existent facts, a Roman vicarius official establishes a power center in the land of the nine ‘nath-i’, that in early historical times became part of the Ui Neill nexus of power.
One decipherment of the genealogical and legendary nonsense of the early Ui Neill traditions that I find convincing focuses on Diarmait mac Cerbaill. In this view Diarmait was a powerful midlands warlord (whose ancestor Conn Cétchathach was his equivalent to Niall) who effectively attached himself and his traditions to the Ui Neill of Tara (self-proclaimed ‘high-kings’ of Ireland). In the subsequent reworkings of the genealogists there was effectively a nuclear fusion between Diarmait and the Ui Neill. The Connachta (ie Diarmait’s people) became part of the Ui Neill. Once this happened, the big ancestor was Niall, Conn now somewhat marginal. As a result, Conn was relegated to the remote peoples of the west that became the land of Conn. Connacht.
That was 7th Century stuff. Fiachrae is earlier. But I do not think it is impossible, nor is it far-fetched, that he may be an example of late-Roman influence in Ireland, and that thinking along these lines at least reminds us that there were two sides to the story and two means of involvement for the Irish in Britain. First, there were raids on Britain; second, the Roman response.
Roman response? If Goidel represents a classis (cohort), then perhaps the Enechglais of Leinster did too, and an early power there was the Ui Garrchon tribe. These were the people of Enech and Garrchu. Inigo and Garcia? Praefecti from Spain or Aquitania? The Lleyn Peninsular, ‘the p. of the Lagin’. Leinster, ‘fifth of the Lagin’. Who could miss that motive for planting pliant leaders in Leinster at this time? If we recall Quintilius Clemens and Paternus, praefecti in northern Britain, the name of the Leinster Ui Loippini tribe might raise eyebrows. These are clearly descended from a Lupinus. Another praefectus?
I do not think any of this is impossible, nor is it far-fetched. Judge for yourself, of course. But bear in mind that nothing is near-fetched in matters of legendary Irish history. Just nothing.