No Keltic name approaches in renown to that of the central figure of the Round Table; yet, in the very dazzle of his brightness, his person has been so much lost, that, as the author of Welsh Sketches observes, "Whereas Peter Schlemihl lost his shadow, Arthur has lost his substance."
    To begin with his name.  He may have been a Romanized Briton named from Arctus, "Arthur's slow wain rolling his course round the pole," and Arcturus, the bear's-tail, far behind him in Boötes; and Arth, perhaps from them, does indeed mean a bear in British...
    Ardrigh was an Erse term for the supreme monarch over their five lesser realms, and is still applied by the native Irish to the king of France,—much as the Greeks were wont to style the Persian monarch the Great King.  This most probably accounts for the term Arviragus, which we picked up by the Romans, and applied to that son of Cymbeline who was really the brave Caradwg.  Ardheer is another form of this same title of the highest chief, and the later critics tell us to consider this as the origin of our hero.
    He is not, indeed, mentioned by Gildas, unless he be the "dragon of the island;" but his omission from that letter is only to his credit, and the individuality of Arthur stands on the testimony of Welsh bards up to his own date, and of universal tradition.
    Nennius mentions Arthur in the sixth century.
    In 720, a person called Eremita Britannus, or the British hermit, is said to have written about King Arthur; the Welsh Mabinogion, or children's tales, were all centering on him; and when, in the early part of the twelfth century, Geoffrey of Monmouth brought out his chronicle, it was translated all over Europe, even into Greek, and furnished myriads of romances, metrical and otherwise. 
    The outline of the Arthur of romance scarcely needs to be here traced; the prince, brought up in concealment, establishing his claim by pulling the sword out of the stone whence no one else could detach it; the Christian warrior, conquering all around, and extending his victories to Rome; the band of Knights; the now and quest of the Holy Grail that breaks the earthly league; the fall and defection of the two most accomplished knights through unhallowed love, the death of one, and the rebellion of the other, the lover of Arthur's own faithless wife,—all opening the way to the fatal treason of the nephew; and the last battle, when the wounded king causes his sword to be thrown into the river, as a signal to the fairies, who bear him away to their hidden isle.  All this is our own peculiar insular heritage of romance ennobled as it has been by old Mallory's prose in the fifteenth century, and in the nineteenth by Tennyson's poetry, the best of all the interpretations of the import of Arthur himself. 
    As to his name, it was not very common even in Wales.  It only came forth as a matter of romance, and was given occasionally either from fancy or policy...
    An old prophecy of Merlin was said to have declared that Richmond should come from Brittany to conquer England, and this prediction caused Henry V. to refuse all requests to allow Arthur, Comte de Richemont, son of the Duke of Brittany, to be ransomed when taken prisoner at Agincourt.  His name of Arthur no doubt added to the danger, and Henry's keen eyesight might have likewise detected in him the military skill which made him so formidable an enemy to the English on his own soil, not theirs.
    When Richmond really came out of Brittany and conquered England, he named his first son Arthur, but that son never wore the British crown, nor did the infant Arthur of Scotland, so named by James V., survive to be known in history.  Arthur, however, had become an occasional name; but it was reserved for the great Arthur Wellesley, whose name had perhaps more to do with the old Art of Erse times than with the king of the Round Table, to make it, as it is at present, one of the most universally popular of English names.  Even the French use it, for its sound, it may be presumed, rather than for its recent distinction, and they have ceased to spell it in the old form, Artus, and adopted our own... (History of Christian Names, Yonge, 1884)