"At least the lack of a sense for the beauty of mountain scenery, which is noticeable in the poetry and travels of the Middle Ages, viewed as a whole, ought to lead us to suspect that this same sense could have been only very slightly apparent in the realm of pictorial art. But ought we not to ascribe the fantastic and romantic art ideal of the old masters, in landscape, rather to their endeavour to transfer the scene and figures of their pictures from reality to an imaginary world?... Even if historical painters like John van Eyck and Memling eagerly introduced jagged rocks and sharp mountain (which apparently they had never seen) into their backgrounds ... it is difficult to recognize any real understanding or even knowledge of the nature of mountains in all this; but simply an old and therefore very conventional form of heroic landscape which was considered as the only suitable one for a large number of subjects."[18] But there is other evidence, besides that to be found in mediæval poetry and travels, which shows to what extent the particular sense for natural beauty, which I am now discussing, was lacking in the Middle Ages. Its absence is also illustrated by the arrangement of castles and other buildings. Mr. d'Auvergne, in his work _The English Castles_, more than once calls attention to this, and instances a tower at Dunstanburgh Castle,[19] which, though commanding a wildly romantic prospect, was selected for the vilest domestic uses. Suddenly, all this is contradicted and reversed. Precisely where man's hand has been, everything is supposed to be polluted, unclean, and ugly; and rough, uncultivated nature, however rugged, however unkempt, is exalted above all that which the human spirit has shaped and trained. How did this change come about? To begin with, let it be said, that it was not quite so sudden as Friedländer would have us suppose. Long before the dawn of the eighteenth century, the very principles that were at the base of European life and aspirations--the principle of the depravity of man, the principle of liberty for liberty's sake, the principle of the pursuit of general truth; and finally, the principle that experience --that is to say, a direct appeal to nature--was the best method of furnishing the mind--all these principles had been leading steadily to one conclusion, and this conclusion Rousseau was the first to embody in his energetic and fulminating protest against culture, tradition, human power and society. And the fact that his doctrine spread so rapidly, that within fifty years of its exposition, with the help of men like Coxe, Ramond de Carbonnières, Étienne de Sénancour, Töppefer, Saussure and Bourit, it had practically become the credo and the passion of Europe, shows how ready the age must have been for the lessons Rousseau taught it.