Poetry owes in every instance its first creative beginning to some great and singular ray of light from symbolical tradition, which, at the same time, illuminates the noble and memorable past, and points forward to the dark and mystical future. For it would be difficult to produce one among the great epic poems of antiquity that does not contain this poetico-prophetic element, and does not touch upon the profound mysteries of both worlds. The next and middle step is occupied by the poetry of sentiment and feeling— that music of the soul or poesy of song in which the calm deep longings and the wild tearing passions of the moment, once plunged and glorified in that immortal element, become eternal. But the height of perfection in the organic development of poetry is marked by the drama. This third and highest form of poetical art has for its subject-matter the whole struggle of human life, which in its vivid representations it aims to realize, and, as it were, to bring bodily before our eyes.
Friedrich von Schlegel, The Philosophy of Life, p. 261.