isation, accent and rhythm began to displace quantity and metre
in Latin versification. Quantitative measures, like the Sapphic and
Hexameter, were composed accentually. The services and music of the
Church introduced new systems of prosody. Rhymes, both single and
double, were added to the verse; and the extraordinary flexibility of
medieval Latin--that sonorous instrument of varied rhetoric used by
Augustine in the prose of the _Confessions_, and gifted with poetic
inspiration in such hymns as the _Dies Irae_ or the _Stabat
Mater_--rendered this new vehicle of literary utterance adequate to
all the tasks imposed on it by piety and metaphysic. The language of
the _Confessions_ and the _Dies Irae_ is not, in fact, a decadent form
of Cicero's prose or Virgil's verse, but a development of the Roman
speech in accordance with the new conditions introduced by
Christianity. It remained comparatively sterile in the department of
prose composition, but it attained to high qualities of art in the
verse and rhythms of men like Thomas of Celano, Thomas of Aquino, Adam
of St. Victor, Bernard of Morlais, and Bernard of Clairvaux. At the
same time, classical Latin literature continued to be languidly
studied in the cloisters and the schools of grammar. The metres of the
ancients were practised with uncouth and patient assiduity, strenuous
efforts being made to keep alive an art which was no longer rightly
understood. Rhyme invaded the hexameter, and the best verses of the
medieval period in that measure were leonine.

The hymns of the Church and the secular songs composed for music in
this base Latin took a great variety of rhythmic forms. It is clear
that vocal melody controlled their movement; and one fixed element in
all these compositions was rhyme--rhyme often intricate and complex
beyond hope of imitation in our language. Elision came to be
disregarded; and even the accentual values, which may at first have
formed a substitute for quantity, yielded to musical notation. The
epithet of popular belongs to these songs in a very real sense, since
they were intended for the people's use, and sprang from popular
emotion. Poems of this class were technically known as _moduli_--a
name which points significantly to the importance of music in their
structure. Imitations of Ovid's elegiacs or of Virgil's hexameters
obtained the name of _versus_. Thus Walter of Lille, the author of a
regular epic poem on Alexander, one of the best medieval