Non satis est, pulchra esse poemata: dulcia _sunto,_ Et quocunque volent, animum auditoris _agunto._ Though the poet was probably quite unconscious of the fact, it is none the less a strange coincidence that, in the very passage in which Horace enforces the obligation that poems should be _dulcia_, we discover a rhyme. Similar rhymes occur in Ovid with still more frequency. Even assuming such to be accidental, the fact remains that they appear to have been not offensive to Roman ears, and might consequently be permitted, although as isolated exceptions, to slip into the composition. Yet the profounder significance of romantic rhyme is absent from such playful exceptions. The former does not assert the recurrent sound merely as sound, but the ideal content or meaning implied in it. And it is precisely this which constitutes the fundamental difference between modern rhyme and the very ancient rhyme of the Hindoos. As for the classical languages, it was after the invasion of barbarism, and on account of the destruction of accentuation and the assertion of that uniquely personal note of emotion referable to Christianity, that the rhythmical system of verse passed into that of rhyme. Thus, in his hymn to the Holy Spirit, Ambrosius entirely regulates the versification according to the accent of the meaning expressed, and breaks into rhyme. The first work of St. Augustine against the Donatists is in the same way a rhymed song; and also the so-called Leonine versicles, as expressly rhymed hexameters and pentameters, are easily distinguishable from the accidental exceptions of rhyme previously noticed. These and other examples like them mark the point of departure of rhyme from the more ancient rhythmical system. (_ββ_) Certain writers have no doubt attempted to trace the origin of the new principle of versification in _Arabian_ literature. The artistic education, however, of the famous poets of the East is of later date than the appearance of rhyme in western Christendom; and any Mohammedan art of a more early time exercised no real influence on the West. We should, however, add that we find from the first in Arabian poetry essential affinities with the romantic principle, in which the knights of Europe, at the time of the crusades, very readily made themselves at home; and consequently it is not difficult to understand how, in the affinity of spiritual tendencies[38] which they shared, and in which the poetry of Eastern Mohammedanism no less than Western Christianity finds its source, though removed in the world from each other, we meet for the first time and on its own independent footing a novel type of verse writing.