Of his own theoretical view of the sonnet, we are unfortunately ignorant, since the last books of his work, 'De vulgari eloquentia,' in which he proposed to treat of ballads and sonnets, either remained unwritten or have been lost. But, as a matter of fact, he has left us in his Sonnets and 'Canzoni' a treasure of inward experience. And in what a framework he has set them! The prose of the 'Vita Nuova,' in which he gives an account of the origin of each poem, is as wonderful as the verses themselves, and forms with them a uniform whole, inspired with the deepest glow of passion. With unflinching frankness and sincerity he lays bare every shade of his joy and his sorrow, and molds it resolutely into the strictest forms of art. Reading attentively these Sonnets and 'Canzoni' and the marvelous fragments of the diary of his youth which lie between them, we fancy that throughout the Middle Ages the poets have been purposely fleeing from themselves, and that he was the first to seek his own soul. Before his time we meet with many an artistic verse; but he is the first artist in the full sense of the word - the first who consciously cast immortal matter into an immortal form. Subjective feeling has here a full objective truth and greatness, and most of it is so set forth that all ages and peoples can make it their own. Where he writes in a thoroughly objective spirit, and lets the force of his sentiment be guessed at only by some outward fact, as in the magnificent sonnets 'Tanto gentile,' etc., and 'Vede perfettamente,' etc., he seems to feel the need of excusing himself. The most beautiful of these poems really belongs to this class - the 'Deh peregrini che pensosi andate,' ('Oh, pilgrims, walking deep in thoughts,' from Vita Nuova.) Even apart from the 'Divine Comedy,' Dante would have marked by these youthful poems the boundary between medievalism and modern times. The human spirit had taken a mighty step towards the consciousness of its own secret life.