Translated as 'Concerning the Ruin of Britain', or as it is sometimes refered to De excidio et conquestu Britanniae ac flebi castigatione in reges, principes, et sacradotes (Concerning the Downfall and Conquest of Britain, or a Mournful Rebuke for Kings, Princes, and Priests)

A 6th century sermon addressed to said kings, princes, and priests whose authorship is ascribed to one Gildas.

Although the earliest surviving manuscripts are much later, it is generally agreed that the work can be dated to around 540 AD, and it is therefore closest thing that we have to a contemporary historical record of Britain of the 5th and 6th centuries. The work is structured as follows;

  • Chapter 1 - The preface
  • Chapters 2-26 - The Historia
  • Chapters 27-110: The Epistola

Unfortunately it is essentially a polemical tract, whose contention is that all the ills of Britain are solely a result of the failure of the Britons to follow the path of righteousness and its purpose is to convince them to return to God when, naturally, God will reward them with victory over their enemies.(Being the Anglo-Saxons of course.)

The Epistola, which makes up most of the work, is one long sermon of invective against five named Romano-British kings and the Anglo-Saxons in general; useful if you are a student of biblically derived Latin insults, but rather tedious otherwise.

As a history it leaves a lot to be desired; no dating is given other than Gildas' reference to the battle of Mons Badonicus taking place 43 years ago in the year of his birth; and the historical narrative is purely anecdotal and is included only to provide support to his evangelical purpose.

Its value is that inbetween the rhetorical lumps of invective it does provide a few scraps of information and it gives a clear indication that at the time of writing Britain was at peace (Gildas refers to a foedus or agreement in place between the Romano-British and the Anglo-Saxons).

Although it has been variously argued that the Historia and the Epistola were written by different authors at different times and that either the whole or one part or another were forgeries it is now generally accepted that De Excidio Britanniae is a genuine work by a single author.