Latin poetry was not at first equally strict. The earlier Roman poets always tried to make the rhetorical and the metrical accent coincide. This was the more easy for them, as their rules of quantity were not yet clearly defined. Only the later Roman poets, and among them especially Horace, who were under the influence of Greek literature, introduced the accurate rules of Hellenic prosody into their own language, and at the same time made the metrical accent quite independent of the rhetorical. A remarkable sign of the difference between the Roman and Greek metrical systems is the way in which the two nations used the most important terms of rhythmical art, arsis and thesis. Aristoxenus, founding his metrical system entirely on the rhythms of dance and music, called arsis the weak part of the metre, because there the dancer raised his foot (αἴρω), and thesis the strong part, when the dancer trod the ground (τίθημι)—exactly contrary to the modern use of these words made familiar by Bentley. The best Roman metrical scholars, such as Atilius Fortunatianus and Terentianus Maurus, on the other hand, led by the rhetorical accent of their language, called arsis the first, and thesis the second, part of the metre, whether weak or strong, following, however, in this the metrical ἐγχειρίδιον of an unknown late-Greek author.[32] The only exception is Martianus Capella, the author of ‘De Nuptiis Philologiæ et Mercurii,’ a work considered, during the middle ages, as a standard authority for all the branches of human knowledge. In his translation of Aristides Quintilianus, he adopted from him the use of arsis and thesis, although it was in direct contradiction to his own definition: ‘Arsis est elevatio, thesis depositio vocis ac remissio.’ The introduction of Greek prosody into the Latin language was simply a matter of art; and its reign could last only so long as the great poets of the classic period kept down the influence of popular poetry. As soon as the unlimited sway of these grand traditions ceased, the original tendencies of the Roman language began to oppose the Greek-Augustan orthodoxy; and this struggle, which lasted for many centuries, ended in the complete overthrow of the ancient prosody. It would lead too far to follow the traces of this process through its different phases; it is enough to say that, at the beginning of the middle ages, the rhetorical as against the metrical accent had more than reconquered its original rights in Latin poetry. In the grand religious songs of mediæval monkish poetry, such as ‘Dies iræ, dies illa’ or ‘Stabat mater dolorosa,’ the verses are measured entirely according to the modern principle of rhetorical accent. Even where the mediæval poets tried to keep up the appearance of ancient versification they could not abstain from yielding to the powerful influence of rising mediæval art. The best example of this fact is the favourite metre of monkish scholars, the Leonine hexameter. The poems written in