Geoffrey of Monmouth, a famous Latin chronicler, who was Archdeacon of Monmouth, was consecrated Bishop of St Asaph in 1152, and died about 1154. His chief work, the Chronicon sive Historia Britonum, was dedicated to Robert, Earl of Gloucester, and must therefore have been composed previous to 1147, the date of the latter's death. It need hardly be said that it possesses little value as history, but there is perhaps but one other book that has exercised, directly or indirectly, so profound an influence upon English literature. Its author professes to have merely translated his work from a chronicle entitled Brut y Brenhined, a History of the Kings of Britain, found in Brittany, and communicated to him by Walter
Calenius, Archdeacon of Oxford; but the work is really nothing more than a masterpiece of the creative imagination working freely on materials found in Gildas, Nennius, and such chroniclers, as well as early legends now difficult to trace. In the dedicatory epistle Geoffrey describes his original as 'a very ancient book in the British tongue, which in a continued regular story and elegant style related the actions of them all, from Brutus, the first king of the Britains, down to Cadwallader the son of Cadwallo.' An abridgment of the Historia was made by Alfred of Beverley as early as 1150, and it was translated into Norman-French by Geoffrey Gaimar in 1154, and by Wace (Li Romans de Brut) with new matter in 1180. Layamon's Brut (early in 13th century) was a semi-Saxon paraphrase of Wace, and Robert of Gloucester's Chronicle was a fresh rhymed paraphrase of the same, which being in the native tongue helped to make the legends invented by Geoffrey widely known. The convincing circumstantiality of the story, and the ingenuity of its etymological connection of existing place-names with eponymous heroes, as well as its irresistible identifications and dovetailings into British history of details of scriptural and of Roman story were sufficient for an uncritical age; and henceforward the Trojan origin of the British people became a point of patriotism and an established historical fact. The stories of King Lear and of Cymbeline, the prophecies of Merlin, and the legend of the famous Arthur in the form in which we know it, owe their origin to the rich imagination of Geoffrey of Monmouth, who still influences us enormously in our Malory, Drayton, Shakespeare, Spenser, Milton, and Tennyson. Chaucer gives 'Englyssh Gauufride' a niche in his House of Fame as being 'besye for to bere up Troye.' Yet the book, even in its own day, did not altogether escape the censure of more severe historians. A Yorkshire monk, William of Newburgh, denounces Geoffrey with honest indignation as having 'lied saucily and shamelessly.' 'A certain writer has come up in our times to wipe out the blots on the Britons, weaving together ridiculous figments about them, and raising them with impudent vanity high above the virtue of the Macedonians and Romans. This man is named Geoffrey, and has the by-name of Arturus, because he cloaked with the honest name of history, coloured in Latin phrase, the fables about Arthur, taken from the old tales of the Bretons, with increase of his own.' Giraldus Cambrensis, writing within fifty years after, distinctly speaks of the book as fabulous, and gives us a somewhat singular but perfectly conclusive proof of this by relating the story of a Welshman at Caerleon named Melerius, who, 'having always an extraordinary familiarity with unclean spirits, by seeing them, knowing them, talking with them, and calling each by his proper name, was enabled through their assistance to foretell future events. . . . He knew when any one spoke falsely in his presence, for he saw the devil as it were leaping and exulting on the tongue of the liar. . . . 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 that book was removed, and the History of the Britons by Geoffrey Arthur was substituted in its place, they immediately reappeared in greater numbers, and remained a longer time than usual on his body and on the book.'
Geoffrey's Chronicle was printed as early as 1508. An English translation by Aaron Thompson appeared in 1718, and was issued in Bohn's 'Antiquarian Library' in 1848.