Who are the Fir Bolg - gods, demons, or men?

Gods?  Demons?  Men?  Myth?  Fiction?  Ancestors of the Belgians?  Let’s find out.


Portrayal of the Fir Bolg in Lebor Gabála Érenn


According to Lebor Gabála Érenn (literally ‘The Book of the Taking of Ireland’ but usually called ‘the Book of Invasions’ in English), the Fir Bolg are descendants of Clann Nemid or ‘the Children of Nemed’, one of the earlier claimed invasions of Ireland.  ‘Nemed’ means ‘the Holy One’ and may be a reference to a pre-Christian ancestor-god.  


According to the tale, the Fir Bolg are driven out of Ireland by the demons known as Fomhóraigh.  They proceed to Greece where they are eventually enslaved and forced to fill and carry bags of dirt for their masters in order to make the land fertile.  They thereby earn the name Fir Bolg or ‘Men of Bags’.  Upon their escape in ships made from these bags, they return to Ireland in three divisions:  Fir Bolg, Fir Domnann, and Gáilióin.  


Having returned to Ireland, the Fir Bolg hold it for 34 years (by my count in reading Lebor Gabála Érenn) until the invasion of the supernatural Tuatha Dé Danann (‘Peoples of the Goddess Danu’).  They are then defeated by the Tuatha Dé Danann in Cath Maige Tuired (the ‘Battle of the Plain of Towers’).


The few survivors of the Fir Bolg “went out of Ireland in flight from the Tuatha Dé Danann; and landed in Ara, and Ile, and Rachra [and Britain] and other islands besides; [and it was they who led the Fomoraig thereafter to the second battle of Magh Tuired] and they were in those islands ... till the Cruithne drove them out.  Then they came to Cairpre Nia Fer (King of Laighin or Leinster) and he gave them lands; but they were unable to remain with him for the heaviness of the tribute which he imposed upon them.  They came in flight before Cairbre under the protection of Ailill and Medb (King and Queen of Connacht) and these gave them lands ...  They were in fortresses and in islands of the sea round about Ireland in this manner, till Cú Chulaind quenched them ...  And of their seed are the three communities who are in Ireland not of Goidelic stock; to wit, the Gabraide of the Suc in Connachta, and the Gáileóin in Laigen.” (1)  The Uí Tairsig were located in Crích Ua bhFailghe, (2)  the territory of the Uí Fhailghe who gave their name to Co. Offaly.


The Fir Bolg in Cét-Chath Maige Tuired


In the mythological tale known as Cét-Chath Maige Tuired or "The First Battle of Magh Tuired", the victorious Tuatha Dé Danann generously give the survivors of the Fir Bolg their choice of the five fifths of Ireland.  The Fir Bolg choose Connacht. (3)


The Fir Bolg in Cath Tánaiste Maige Tuired


In this great mythological tale of the ‘Second Battle of Magh Tuired’, the text early on notes that “those of the Fir Bolg who escaped from the (first) battle (of Magh Tuired) fled to the Fomoire, and they settled in Arran and in Islay and in (the Isle of) Man and in Rathlin.” (4)


The Fomhóraigh demons and Tuatha Dé Danann gods then proceed to have their showdown.  The Fir Bolg fight on the side of the Fomhóraigh and lose.  One of the leaders of the Fomhóraigh is Indech mac Dé Domnann whose name can be translated as ‘Indech son of the God of the Domnann’.


The Actual Fir Bolg


Given their close association with Fomhóraigh demons and Tuatha Dé Danann gods, it is understandable that the Fir Bolg are often assumed to be only a myth.


However, unlike the Fomhóraigh and Tuatha Dé Danann, there is no doubt that the Fir Bolg are an actual, historical people whose descendants are alive and well and identifiable among us.  The Fir Domnann left their name on various places including Inbhear Domnainn (the estuary of Malahide Bay) in Co. Dublin and Iorrus Domnainn (‘Erris’) in Co. Mayo.  They are associated by modern scholars with the Dumnonii of Britain.


It can be demonstrated that the Fir Domnann and Gáilióin were originally branches of the Laighin who gave their name to Leinster (Laighin-ster) and also apparently to the Lleyn Peninsula in northern Wales.  Note, for example, the following verse written in a text of Féineachas (‘Brehon Law’) in the 8th Century:


Batar trí prímcheinéla i nHére, .i. Féini 7 Ulaith 7 Gáilni .i. Laigin. (5)

There were three primary kinships in Ireland, i.e., the Féini and Ulaidh and Gáilióin, i.e., the Laighin.


Specific Irish tuatha (peoples / tribes), clanna (clans), and finte (extended families) were identified in the historic era as Fir Bolg, the hereditary enemies of the Gaeil, and denied rights and privileges under Féineachas (‘Brehon Law’) on that basis.  The Laighin eventually received and accepted a genealogy claiming their descent from Gaedheal Glas.  This entitled them, as Gaeil, to full rights and privileges under Féineachas.  Somehow, the Fir Domnann and Gáilióin did not receive or refused to accept a Gaelic genealogy, and so were classified as Fir Bolg.  The Fir Bolg origin of the following aitheach-thuatha (literally, 'tribute-paying peoples,' which is to say 'subject-peoples') is apparent: (6)


- the Bolgraige or 'Descendants of (the god) Bolg,' an historic aitheach-thuath ('tribute-paying people') of Tír Chonaill, now called Co. Donegal;


- the Bolgthuath Badhbhnai or 'Bolg-People of the Descendants of (the goddess) Badhbh,' an historic aitheach-thuath of Connacht;


- the Bolgthuath Echtghe or 'Bolg-People of Horse-God,' an historic aitheach-thuath of Connacht;


- the Bolgthuath Muige Luirg an Daghda or 'Bolg-People of the Plain of the Track of the Daghda,' an historic aitheach-thuath of the plain called Moylurg in English in what is now Co. Roscommon in the province of Connacht.  


The Fir Bolg origin of the Ó hEdirsceoil ('O'Driscoll') family is apparent in their clan-name.  They are the Ó hEdirsceoil of the Uí Builc ('Descendants of Bulc') of the Corcu Loígde ('Seed of the Calf-Goddess') who ruled Munster before the Eoghanachta. (7)  The barely-Christianized genealogy of the Corcu Loígde found in Rawlinson B.502 has them descend from Sidebulg or Sidebulc ('Bolg of the Sidh,' i.e., Bolg of the gods who went into the Sidh-mounds), great-grandson of Lugh son of Eithliu. (8)  In Irish mythology, as Elizabeth Gray points out, "Lug is known both by his patronymic (Lug mac Céin) and by his matronymic (Lug mac Ethnenn, or mac Ethlenn), which in time came to be considered an alternative patronymic..." (9)        


In addition, with the 2004 publication of Dubhaltach Mac Fhirbhisigh’s great 17th century genealogical work, Leabhar na nGenealach as ‘The Great Book of Genealogies’ by De Búrca Books of Dublin, it is again possible to identify specific finte (extended families), clanna (clans), and tuatha (peoples / tribes) of the Fir Bolg.


Origin of the Fir Bolg


It is likely, but difficult to prove, that the main stem of the Fir Bolg (but not the Fir Domnann and Gáilióin) are a branch of the Belgae who fought Caesar and gave their name to Belgium.  If so, some may have come to Ireland directly from Belgic Gaul and others may have come via Celtic Britain (where many remained and were described by Caesar as a problem for Roman rule).  T.F. O'Rahilly noted that "According to Irish tradition they were the same stock as the Britons; and their own invasion-legend tells how their ancestor Lugad came from Britain and conquered Ireland." (10)  But can we find further proof?  I think we can.  Here’s an example.


Ptolemy of Alexandria wrote his geography of Ireland in the 2nd century A.D. but, as pointed out by T.F. O’Rahilly, it may be based on the lost work of Pytheas of Massalia who voyaged to the 'Pretanic Isles' (i.e., the 'British Isles') about 325 B.C.  Either way, Ptolemy's geography includes a short list of Celtic tribes in Ireland whose names appear to be represented in the P-Celtic language of Gaul or Britain rather than the Q-Celtic of Ireland.  Of these, Ptolemy reported that the Manapii were located in the east of Ireland, approximately in what is now Co. Wicklow.


Although we don't have absolute proof, a number of scholars have long assumed that these Manapii are a branch of the Menapii, a tribe of the Belgae of northern Gaul located about the mouth of the Rhine who fiercely resisted Caesar until 54 B.C.  The Menapii also produced Marcus Aurelius Mausaeus Carausius, a prominent military commander of the Roman Empire who declared himself Emperor in 286 A.D.    As would be expected as they switched from speaking P-Celtic Gaulish to Q-Celtic Irish, they are known in Ireland in the early historic period as the Manaig, with Monaig and Monach being variations in spelling.  


Over time, as noted by T.F. O'Rahilly, the Manapii or Manaig of Ireland trekked north from Leinster (in which Cúigiú or 'Fifth' of Ireland we find Co. Wicklow), leaving their name on Druim Monach ('Drumanagh') and on a ford called Scenmenn Monach in the north of Co. Dublin.  They eventually became the Monaig/Manaig in Uí Echach Ulad (west Co. Down) and also in the neighborhood of Loch Éirne ('Lough Erne') in what is now Co. Fermanagh.  Later they became known as the Fir Manach and gave their name to Co. Fermanagh.  


In Irish seanchas (law, history, genealogy), the Manappi or Manaig are classified as a branch of the Fir Bolg, just as the Menapii were a branch of the Belgae on the Continent.   In my opinion, this traditional classification, this traditional association of Manappi and Bolg, defies mere coincidence.  In other words, I believe that this classification positively identifies the Manaig of Ireland as Menapii, and the Fir Bolg or Bolg of Ireland as Belgae.




Over the years, I've met various Fir Bolg.  I'm even a fan of the early career of a famous actress who is descended from the Fir Bolg.  I'll bet you know plenty of Fir Bolg, too.





1.   Lebor Gabála Érenn, edited by R.A.S. Macalister.  London:  Irish Texts Society, 1938-1956. Volume IV, pps. 35-36

2.   Céitinn, Seathrún.  Foras Feasa Ar Éirinn – the History of Ireland, edited by David Comyn and Patrick S. Dineen.  London:  Irish Texts Society, 1902-1914, Volume I, p. 200),

3.   For an English translation of Cét-Chath Maige Tuired, see Mary Jones’ excellent website at http://www.maryjones.

us/ctexts/1maghtured.html .

4.  Cath Maige Tuired: The Second Battle of Mag Tuired.  edited by Elizabeth A. Gray.  Naas, Co. Kildare:  Irish Texts Society

(Cumann na Sgríbheann Gaedhilge), No. 52, p. 27

5.  Byrne, Francis John.  Irish Kings and High-Kings.  Dublin:  Four Courts Press, 1973. p. 106

6.  O’Rahilly, T.F., Early Irish History and Mythology.  Dublin:  The Dublin Institute for Advanced Studies, 1946.  p. 43

7.  O'Rahilly, p. 49

8.  O'Brien, Michael A., editor.  Corpus Genealogiarum Hiberniae.  Dublin:  Dublin Institute for Advanced Studies, 1962.  p. 256, par.

155 a 3, lines 6-7

9.  Cath Maige Tuired - The Second Battle of Mag Tuired.  edited by Elizabeth A. Gray, p. 126

10.  O'Rahilly, p. 16, par. (2)



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