Blake & Lloyd take it as read that Geoffrey of Monmouth’s Historia Regum Brittanie (‘History of the Kings of Britain’) is exactly what it claims to be: a translation into Latin of ‘a certain very ancient book written in the British language’ (HRB i.1), ‘the British treatise already referred to’ (HRB xi.1) and ‘the book in the British language… from Britannia… composed with great accuracy about the doings of these princes and in their honour’ (HRB xii.20). The problem has been—since the publication of his work—that no one knows what the ‘ancient book’ was.

Blake and Lloyd’s solution to the problem is simple. They propose that the group of texts usually known as Brut y Brenhinedd (‘The History of the Kings’) also derive from Geoffrey’s source. However, the academic consensus is that they are translations from Geoffrey’s Latin text, omitting his dedications and harmonising the narrative with existing Welsh traditions. All versions omit any reference to Geoffrey and also his preface, his comments throughout the work and the epilogue found in some of the Latin texts (HRB xii.20).

This in itself is not enough to prove that the Brutiau are nothing more than translations of Geoffrey. Indeed, it could be argued that Geoffrey added the preface, the scattered comments and the epilogue. However, they follow exactly the same narrative structure. Different versions insert different additional material according to the way in which it fits his work. There are inconsistencies between Welsh tradition and Geoffrey, which some Brutiau silently emend, while others admit to the difficulties. There is one instance that proves the Brutiau to be translations from Latin into Welsh: the alteration of Geoffrey’s Budicius, king of Armorica, to Emhyr Llydav. The words emyr Llydaw mean ‘King of Llydaw’ and it is evident that all versions of the Brut derive from a text in which the name of Budicius has been lost: Geoffrey cannot have inserted it.