The ‘HISTORIA BRITTONUM’ (History of the Britons), written in early-9th century Wales, has survived, to a greater or lesser extent and with many variations, in more than thirty manuscripts.* The principal, i.e. fullest, text is to be found in Harleian MS 3859 (in the British Library, London) – which also contains the A-text of the ‘Annales Cambriae’ and the earliest Welsh collection of royal genealogies. Though the manuscript dates from c.1100, internal evidence suggests that the ‘Historia’ text was originally compiled c.829.* Traditionally, on the strength of a preface that features in just a handful of manuscripts (Harleian MS 3859 is not one of them), the work is attributed to Nennius:*
“I, Nennius, disciple of St Elvodugus, have endeavoured to write some extracts which the dulness of the British nation had cast away, because teachers had no knowledge, nor gave any information in their books about this island of Britain. But I have made a heap of all that I could find as well from the annals of the Romans as from the chronicles of the sacred fathers, Hieronymus, Eusebius, Isidorus, Prosper, and from the annals of the Scots [i.e. Irish] and Saxons, and from our own ancient traditions. Many teachers and scribes have attempted to write this, but somehow or other have abandoned it from its difficulty, either on account of frequent deaths, or the often-recurring calamities of war. I pray that every reader who shall read this book, may pardon me, for having attempted, like a chattering jay, or like some weak witness, to write these things, after they had failed. I yield to him who knows more of these things than I do.”
‘Historia Brittonum’ Preface (translation by J.A. Giles)
None of the surviving manuscripts of this, so-called, ‘Nennian recension’ is earlier than the 12th century, though a text of the recension was translated from Latin into Middle Irish during the second half of the 11th century.* The attribution to Nennius cannot, therefore, be traced any further back than the mid-11th century, and seems likely be a late accretion. Nevertheless, “a heap” might be considered a reasonable description of the miscellaneous assortment of material, riddled with errors and inconsistencies, presented by the ‘Historia Brittonum’.
The contents of Harleian MS 3859 can be categorized as follows –
§§1–6: The Six Ages of the World.   §§7–18: British, Irish and Pictish origins.   §§19–30: Roman Britain.
§§31–49: The Adventus Saxonum story.   §§50–55: Life of St Patrick.   §56: The campaigns of Arthur.
§§57–61: Genealogies of Anglo-Saxon kings.   §§62–65: Northumbria.   §66: Chronological calculations.
§66a: The 28 cities of Britain.   §§67–76: The Wonders of Britain, Anglesey and Ireland.*
“Though it is clearly intended to provide a survey of the past history of the British it is an ill-synthesized and ill-digested work; the compiler gathered together and transcribed more or less relevant documents of very different types. Its contents, therefore, are very varied ...”
Wendy Davies ‘Wales in the Early Middle Ages’ (1982) Appendix
Indeed, a good deal of the ‘Historia’ is clearly fantasy.
“Much of the work consists of passages which, save that they lack the introduction ‘once upon a time’, have all the historical reliability of fairy-stories.”
A.S. Esmonde Cleary ‘The Ending of Roman Britain’ (1989) Chapter 5
On the other hand, it must, so the theory goes, also contain historical nuggets.
“Considerations of plausibility, the Historia's relation to earlier sources, its chronology and compatibility with the archaeological evidence – all these combine to suggest that the Historia does contain genuine early information, albeit in a very adulterated form.”
Michael E. Jones ‘The End of Roman Britain’ (1996) Appendix 4
“The problem is that an objective method of sorting the wheat from the chaff has never been forthcoming; you pays your money and you takes your choice of what commends itself to you at the time.”
A.S. Esmonde Cleary ‘The Ending of Roman Britain’ Chapter 5
“It is impossible, therefore, to generalize about the value of the Historia Brittonum. On the one hand it provides first-hand evidence of the attitude to history writing of a Welshman of the early ninth century. On the other it presents us with edited documents of varying dates and provenances whose origins are not yet sufficiently understood; at the least, however, the latter indicates some of the materials that were available to the historian in the early ninth century.”
Wendy Davies ‘Wales in the Early Middle Ages’ Appendix
There is (in §16) a reference suggesting that at the time of writing it was the fourth year of Mermini regis, i.e. Merfyn Frych, king of Gwynedd. The ‘Annales Cambriae’ indicate that Merfyn's predecessor, Hywel, died in 825, hence Merfyn's fourth year is c.829.
In the first chapter of her ‘Historical Writing In England, c.550 to c.1307’ (1974), Antonia Gransden writes:
“The evidence in the work itself for Nennius's authorship is the preface, which occurs in only four of the thirty-three manuscripts known to modern editors, and of these four manuscripts only two are of textual value.”
Other versions of the ‘Historia Brittonum’ spuriously attribute the work to Gildas, or “Marcus the Anchorite, a holy bishop of that people [i.e. the Britons]”, whilst the, now lost, Chartres Manuscript talked of “excerpts made by the son of Urien (filius Urbagen) from the Book of the Blessed Germanus”.
David Dumville, in a paper entitled ‘Historia Brittonum: an Insular History from the Carolingian Age’ (in ‘Historiographie im frühen Mittelalter’, 1994):
“... the earliest manuscript witnesses belong to the eleventh century and are not Welsh. They represent the ‘Chartres’ and ‘Vatican’ recensions.”
The Chartres Manuscript itself was destroyed during World War II.
Probably later-10th century – during the reign (in Deheubarth, 950–988) of Owain ap Hywel Dda.
The Irish text is called the ‘Lebor Bretnach’, but is frequently referred to as the ‘Irish Nennius’.
Elvodugus (Elfoddw) is described as “archbishop in the Gwynedd region” in his ‘Annales Cambriae’ obituary (the year 809).
J.A. Giles translates this version of the preface under the title ‘The Apology of Nennius’. The Rev. Dr Giles, in fact, translates Nennius' famous comment, “I have made a heap of all that I could find”, rather more politely: “I have got together all that I could find”.
David Dumville writes:
“Accretion is one of the features which recurs determinedly throughout the textual history of the Historia Brittonum... However, the Historia never became a large text ... More commonly, it was the fate of this work to be shortened by redactors. The section most particularly at risk was that which gave the Anglo-Saxon royal genealogies and an account of the Anglo-British wars involving Northumbrian kings of the sixth and seventh centuries [i.e. §§57–65]; the next most vulnerable was the concluding description of the natural marvels of the British Isles [i.e. §§67–76].”
‘Historia Brittonum: an Insular History from the Carolingian Age’