Geoffrey's structuring and shaping of the
Merlin and
Arthur myths engendered their vast popularity which continues today, and he is generally viewed by scholars as the major establisher of the Arthurian canon. The
Historys effect on the legend of King Arthur was so vast that Arthurian works have been categorised as "pre-Galfridian" and "post-Galfridian", depending on whether or not they were influenced by him.
Historia Regum Britanniae Geoffrey wrote several works in Latin, the language of learning and literature in Europe during the medieval period. His major work was the (
The History of the Kings of Britain), the work best known to modern readers. It relates the purported history of Britain, from its first settlement by
Brutus of Troy, a descendant of Trojan hero
Aeneas, to the death of
Cadwaladr in the 7th century, covering
Julius Caesar's
invasions of Britain, kings
Leir and
Cymbeline, and one of the earliest developed narratives of
King Arthur. Geoffrey claims in his dedication that the book is a translation of an "ancient book in the British language that told in orderly fashion the deeds of all the kings of Britain", given to him by
Walter, Archdeacon of Oxford, but modern historians have dismissed this claim. It is likely, however, that the Archdeacon did furnish Geoffrey with some materials in the Welsh language which helped inspire his work, as Geoffrey's position and acquaintance with him would not have permitted him to fabricate such a claim outright. Much of it is based on the
Historia Britonum, a 9th-century Welsh-Latin historical compilation,
Bede's
Ecclesiastical History of the English People, and
Gildas's 6th-century polemic , expanded with material from
bardic oral tradition and genealogical tracts, and embellished by Geoffrey's own imagination. In an exchange of manuscript material for their own histories,
Robert of Torigny gave
Henry of Huntingdon a copy of
History, which both Robert and Henry used uncritically as authentic history and subsequently used in their own works, by which means Geoffrey's fictions became embedded in popular history.
The History of the Kings of Britain is now usually considered a literary forgery containing little reliable history. This has since led many modern scholars to agree with
William of Newburgh, who wrote around 1190 that "it is quite clear that everything this man wrote about Arthur and his successors, or indeed about his predecessors from
Vortigern onwards, was made up, partly by himself and partly by others." Other contemporaries were similarly unconvinced by Geoffrey's
History. For example,
Gerald of Wales recounts the experience of a man possessed by demons: "If the evil spirits oppressed him too much, the
Gospel of St John was placed on his bosom, when, like birds, they immediately vanished; but when the book was removed, and the
History of the Britons by 'Geoffrey Arthur' [as Geoffrey named himself] was substituted in its place, they instantly reappeared in greater numbers, and remained a longer time than usual on his body and on the book." Geoffrey's major work was nevertheless widely disseminated throughout medieval Western Europe; Acton Griscom listed 186 extant manuscripts in 1929, and others have been identified since. It enjoyed a significant afterlife in a variety of forms, including translations and adaptations such as
Wace's Old Norman-French
Roman de Brut,
Layamon's Middle English
Brut, and several anonymous
Middle Welsh versions known as ''
("Brut of the Kings''"). where it was generally accepted as a true account. In 2017,
Miles Russell published the initial results of the Lost Voices of Celtic Britain Project established at
Bournemouth University. The main conclusion of the study was that the
Historia Regum Britanniae appears to contain significant demonstrable archaeological fact, despite being compiled many centuries after the period that it describes. Geoffrey seems to have brought together a disparate mass of source material, including folklore, chronicles, king-lists, dynastic tables, oral tales, and bardic praise poems, some of which was irrevocably garbled or corrupted. In doing so, Geoffrey exercised considerable editorial control, massaging the information and smoothing out apparent inconsistencies in order to create a single grand narrative which fed into the preferred narrative of the Norman rulers of Britain. Much of the information that he used can be shown to be derived from two discrete sources: • the orally transmitted, heroic tales of the
Catuvellauni and
Trinovantes, two essentially pre-Roman tribes inhabiting central south-eastern Britain at the very end of the
Iron Age; • the king-lists of important
post-Roman dynasties that ruled territories in western Britain. Stretching this source material out, chopping, changing and re-editing it in the process, Geoffrey added not just his own fictions but also additional information culled from Roman and early medieval histories and early medieval writers such as Gildas and Bede.
Other writings Geoffrey's earliest writing was probably the ''
(Prophecies of Merlin
) which he wrote before 1135, and which appears both independently and incorporated into The History of the Kings of Britain''. It consists of a series of obscure prophetic utterances attributed to
Merlin which he claimed to have translated from an unspecified language. The third work attributed to Geoffrey is the hexameter poem (
Life of Merlin), based more closely on traditional material about Merlin than the other works. Here he is known as Merlin of the Woods (
Merlinus Sylvestris) or Scottish Merlin (
Merlinus Caledonius) and is portrayed as an old man living as a crazed and grief-stricken outcast in the forest. The story is set long after the timeframe of the
Historys Merlin, but the author tries to synchronise the works with references to the mad prophet's previous dealings with
Vortigern and Arthur. The
Vita did not circulate widely, and the attribution to Geoffrey appears in only one late-13th-century manuscript, but it contains recognisably Galfridian elements in its construction and content, and most critics recognise it as his. ==In popular culture==