An additional proof of the superiority of this great genius may be drawn from the commentaries upon his works. We are there surprised to see his most enthusiastic admirers incapable of appreciating his real grandeur. Dante himself, in his Latin treatise entitled _De Vulgari Eloquentia_, appears to be quite unconscious of the extent of his services to the literature of his country. Like his commentators, he principally values himself upon the purity and correctness of his style. Yet he is neither pure nor correct; but, what is far superior to either, he had the powers of creative invention. For the sake of the rhyme, we find him employing a great number of barbarous words, which do not occur a second time in his verses. But, when he is himself affected, and wishes to communicate his emotions, the Italian language of the thirteenth century, in his powerful hands, displays a richness of expression, a purity, and an elegance which he was the first to elicit, and by which it has ever since been distinguished. The personages whom he introduces are moving and breathing beings; his pictures are nature itself; his language speaks at once to the imagination and to the judgment; and it would be difficult to point out a passage in his poem which would not form a subject for the pencil. The admiration of his commentators has also been abundantly bestowed upon the profound learning of Dante, who, it must be allowed, appears to have been master of all the knowledge and accomplishments of the age in which he lived. Of these various attainments, his poem is the faithful depository, from which we may infer, with great precision, the progress which science had at that time made, and the advances which were yet necessary to afford full satisfaction to the mind.[e]