But from its very earliest stages the Lancelot story came into contact with another and highly popular tale, the legend of Perceval. The earlier and later biographical forms (Lanzelet and the prose Lancelot) and the episodic romances (Le cerf au pied blanc and Morien) show traces of contact, direct or indirect, with this story; while the precise statements of certain MSS.[210] make it quite clear that even at an advanced stage of its evolution the Lancelot legend formed part of a cycle of which the most important member was the story of Perceval and the Grail.
This continued contact with the Perceval story, with the resulting developments, appears to be the most important factor in the evolution of the Lancelot legend, and one which has hitherto been overlooked.
So far as the evidence at our disposal permits us to trace it, the course of development seems to have been the following. Gradually the legend of the Grail,[211] originally foreign to the Perceval story, completely dominated that story and changed the character of the hero, who became transformed into an ascetic celibate; while, on the other hand, the growing popularity of the Lancelot story had reacted prejudicially on the position alike of Perceval and the still earlier hero Gawain as knights of King Arthur's court. Eventually the two competing centres of romantic interest were Lancelot and the Grail, and it became necessary to combine them in such a manner that the latter, while still retaining its sacrosanct character, should yet contribute to heighten the fame of the popular 'secular' hero.
Such a combination was possible, under certain conditions, and an ingenious writer, perceiving this possibility, turned it to account by inventing the Galahad Queste, which, poor and inadequate as a Grail romance, yet as a contribution to the Lancelot cycle had a very certain and decided value. It put the final touch to the evolution of the hero by enabling him to take part, under circumstances which should vicariously increase his fame, in the great adventure of the Arthurian cycle, the Grail Quest; it also restored superficially the unity of the cycle, which had been injured by the cleavage between the Grail and the other sections, caused by the growing popularity of Lancelot as compared with Perceval.
While Gawain and Perceval were the leading heroes of the Arthurian cycle, a Perceval Queste was natural; but as soon as these two were supplanted in the popular favour by Lancelot, the Perceval Queste, as an integral part of the cycle, became more and more inharmonious. A change in the interest of the later Lancelot development was inevitable, and that the change took place precisely at the psychological moment is, I think, proved by the practically universal welcome accorded to the Galahad Queste. With unanimous consent the Perceval Queste appears to have been discarded as a part of the cycle, although in its independent form it still retained its popularity.
Naturally all the branches of the cycle into which the new Queste had been adopted were more or less affected by it; in some cases the references to the coming Grail Winner were more or less vague, and would apply as well to the later as to the earlier hero; in other instances they were amplified but not altered, thus introducing confusion into the text (this is, I suspect, the case with the Merlin Suite). The romances that represented the Early History, as introduction to the Queste, were naturally the most affected, and at the present moment it is extremely difficult to decide whether the Grand S. Graal be a direct amplification of the Joseph of Arimathea, constructed with a view to the Galahad Queste, or whether, in its existing form, it depends upon an intermediate version the données of which would agree with the cyclic Perceval.
In any case the 'net' result was, I believe, the substitution of the name of the supposed author of the Queste, Walter Map, for that of the traditional author of the earlier Perceval-Grail story, Robert de Borron; and to ascribe to Map that cyclic redaction of the Arthurian romances which had previously been ascribed to de Borron.
I think that much of the difficulty hitherto experienced in determining the order and date of the various Grail romances has arisen from our very natural tendency to regard these romances as a group apart, and to compare them exclusively with each other; whereas they should be treated as members of the cycle, and compared with the other branches of the cycle. More especially is this the case with the Galahad Queste; treated as a Grail romance proper, it is inexplicable, and appears to represent no possible step that can be postulated in the natural evolution of the Grail legend. We could imagine the honour transferred from father to son (as a matter of fact it is Lohengrin and not Galahad who should be the successor to Perceval); but this sudden break in the tradition by which the honour passes to the race of King Ban, no relationship between Perceval and Lancelot being previously hinted at, is, considered in itself, most perplexing. On the other hand, treat the Queste as an integral part of the Lancelot cycle, and it not only explains itself, but gives us valuable assistance in 'placing' the earlier versions.
At the same time it is obvious that the theory here advanced only applies to the later stages of the Grail tradition; it does not touch the problem of the origin of the Grail itself, or its first connection with Perceval.