Malory did a work of high value in editing the confused mass of earlier fiction, lopping off its excrescences and redundancies, reducing its coarseness of speech, and producing from its many stories and episodes a coherent and continuous narrative, in which the adventures of the Round Table Knights are deftly interwoven with the record of the birth, life, and death of the king, round whom as the central figure all these knightly champions revolve. Malory seems to have used as the basis of his work perhaps one, perhaps several, old French prose romances, and possibly also material derived from Welsh and English ballads. Such material in his day was doubtless abundant. Geoffrey had drawn much of his legendary history from the ancient Welsh ballads. The mass of romantic fiction which he called history became highly popular, first in Brittany, and then in France, the Trouveres making Arthur, Lancelot, Tristram, Percival, and others of the knightly circle the heroes of involved romances, in which a multitude of new incidents were invented. The Minnesingers of Germany took up the same fruitful theme, producing a "Parzivale," a "Tristan and Isolt," and other heroic romances. From all this mass of material, Malory wrought his "Morte Darthur," as Homer wrought his "Iliad" from the preceding warlike ballads, and the unknown compiler of the "Nibelungenlied" wrought his poem from similar ancient sources.
Malory was not solely an editor. He was in a large sense a creator. It was coarse and crude material with which he had to deal, but in his hands its rude prose gained a degree of poetic fervor. The legends which he preserves he has in many cases transmuted from base into precious coin. There is repulsive matter in the old romances, which he freely cuts out. To their somewhat wooden heroes he gives life and character, so that in Lancelot, Gawaine, Dinadan, Kay, and others we have to deal with distinct personalities, not with the non-individualized hard-hitters of the romances. And to the whole story he gives an epic completeness which it lacked before. In the early days of Arthur's reign Merlin warns him that fate has already woven its net about him and that the sins of himself and his queen will in the end bring his reign to a violent termination, and break up that grand fellowship of the Round Table which has made Britain and its king illustrious. This epic character of Malory's work is pointed out in the article "Geoffrey of Monmouth" in the "Encyclopædia Britannica," whose writer says that the Arthurian legends "were converted into a magnificent prose poem by Sir Thomas Malory in 1461. Malory's _Morte Darthur_ is as truly _the_ epic of the English mind as the _Iliad_ is the epic of the Greek mind."