The King Arthur Character does not significantly predate "The History of the Kings of Britain"

I regret that my partner was unable to participate this round. I hope that he is well, and will return soon. It is unfortunate that I require the evidence that was to be presented by my partner here, so that the counter evidence could be evaluated. Since I have been afforded a “free round,” with no rebuttals needed, I can do something I otherwise could not: I can describe the way that historians who lived at the same time as Geoffrey reacted to his assertions. These contemporaries seem very surprised to have heard of his “King Arthur.” It seems that these men were surprised to learn of the existence of “King Arthur,” although they recognized some resemblance to Welsh folklore – they did not recognize any such monarch. To illustrate this, I will present the following statement, from William of Newburgh, who was so comically outraged by Geoffrey of Monmouth’s descriptions of King Arthur, that he dedicated the Preface to his own work, "Historia Rerum Anglicarum" to denouncing Geoffrey. It cannot be argued that the King Arthur stories were well known if these contemporaries had not heard of him. I will quote as much of the Preface as I am able, because any fan of King Arthur will enjoy reading the hilarious venom and rage with which William discusses the subject. There is no better rebuttal to Geoffrey’s fanciful history than this, as told by as reputable a historian that can be found in the 12th century, William of Newburgh: “A writer in our times has started up and invented the most ridiculous fictionsconcerning (the Britons), and with unblushing effrontery, extols them far abovethe Macedonians and Romans. He is called Geoffrey, surnamed Arthur, from havinggiven, in a Latin version, the fabulous exploits of Arthur, and endeavored todignify them with the name of authentic history…” Moreover, no one but a person ignorant of ancient history, when he meets with that bookwhich he calls the History of the Britons, can for a moment doubt howimpertinently and impudently he falsifies in every respect Now, since it is evident that these facts are established with historicalauthenticity by the venerable Bede, it appears that whatever Geoffrey haswritten, subsequent to Vortigern, either of Arthur, or his successors, orpredecessors, is a fiction, invented either by himself or by others, andpromulgated either through an unchecked propensity to falsehood, or a desire toplease the Britons, of whom vast numbers are said to be so stupid as to assertthat Arthur is yet to come. He also mentions Uther Pendragon, his brother, ashis successor, whom, he pretends, reigned with equal power and glory, adding avast deal from Merlin, out of his profuse addiction to lying. On the decease ofUther Pendragon, he makes his son Arthur succeed to the kingdom of Britain --the fourth in succession from Vortigern, in like manner as our Bede placesEthelberht, the patron of Augustine, fourth from Hengist in the government ofthe Angles. Therefore, the reign of Arthur, and the arrival of Augustine inEngland, ought to coincide.But how much plain historical truth outweighs concerted fiction may, in thisparticular, be perceived even by a purblind man through his mind's eye.Moreover, he depicts Arthur himself as great and powerful beyond all men, andas celebrated in his exploits as he chose to feign him. First, he makes himtriumph, at pleasure, over Angles, Picts, and Scots; then, he subdues Ireland,the Orkneys, Gothland, Norway, Denmark, partly by war, partly by the singleterror of his name. To these he adds Iceland, which, by some, is called theremotest Thule, in order that what a noble poet flatteringly said to the RomanAugustus, "The distant Thule shall confess thy sway," might apply tothe British Arthur. Next, he makes him attack, and speedily triumph over, Gaul-- a nation which Julius Caesar, with infinite peril and labor, was scarcelyable to subjugate in ten years -- as though the little finger of the Britishwas more powerful than the loins of the mighty Caesar. After this, withnumberless triumphs, he brings him back to England, where he celebrates hisconquests with a splendid banquet with his subject-kings and princes, in thepresence of the three archbishops of the Britons, that is London, Carleon, andYork -- whereas, the Britons at that time never had an archbishop. Augustine,having received the pall from the Roman pontiff, was made the first archbishopin Britain; for the barbarous nations of Europe, though long since converted tothe Christian faith, were content with bishops, and did not regard theprerogative of the pall. Lastly, the Irish, Norwegians, Danes, and Goths,though confessedly Christians, for a long while possessed only bishops, and hadno archbishops until our own time.Next this fabler, to carry his Arthur to the highest summit, makes him declarewar against the Romans, having, however, first vanquished a giant of surprisingmagnitude in single combat, though since the times of David we never read ofgiants. Then, with a wider license of fabrication, he brings all the kings ofthe world in league with the Romans against him; that is to say, the kings ofGreece, Africa, Spain, Parthia, Media, Iturea, Libya, Egypt, Babylon, Bithynia,Phrygia, Syria, Boeotia, and Crete, and he relates that all of them wereconquered by him in a single battle; whereas, even Alexander the Great,renowned throughout all ages, was engaged for twelve years in vanquishing onlya few of the potentates of these mighty kingdoms. Indeed, he makes the littlefinger of his Arthur more powerful than the loins of Alexander the Great; moreespecially when, previous to the victory over so many kings, he introduces himrelating to his comrades the subjugation of thirty kingdoms by his and theirunited efforts; whereas, in fact, this romancer will not find in the world somany kingdoms, in addition to those mentioned, which he had not yet subdued.Does he dream of another world possessing countless kingdoms, in which the circumstanceshe has related took place? Certainly, in our own orb no such events havehappened. For how would the elder historians, who were ever anxious to omitnothing remarkable, and even recorded trivial circumstances, pass by unnoticedso incomparable a man, and such surpassing deeds? How could they, I repeat, bytheir silence, suppress Arthur, the British monarch (superior to Alexander theGreat), and his deeds? Since, therefore, the ancient historians make not the slightest mention of thesematters, it is plain that whatever this man published of Arthur and of Merlinare mendacious fictions, invented to gratify the curiosity of the undiscerning.Moreover, it is to be noted that he subsequently relates that the same Arthurwas mortally wounded in battle, and that, after having disposed of his kingdomhe retired into the island of Avallon, according to the British fables, to becured of his wounds; not daring, through fear of the Britons, to assert that hewas dead -- he whom these truly silly Britons declare is still to come. Of thesuccessors of Arthur he feigns, with similar effrontery, giving them themonarchy of Britain, even to the seventh generation, making those noble kingsof the Angles (whom the venerable Bede declares to have been monarchs ofBritain) their slaves and vassals.Therefore, let Bede, of whose wisdom and integrity none can doubt, possess ourunbounded confidence, and let this fabler, with his fictions, be instantlyrejected by all.” William of Newburgh, "HistoriaRerum Anglicarum" c 1198 (Preface