Beethoven, Op. 24, Monophonic Style. Sonata for Violin and Piano. Melody enters in measure one with subordinate accompaniment. =Search for Structural Principles=.—While this question of the relation of polyphonic music to modern music may not apply to the first step in the development of the polyphonic style, yet it furnishes a preface to a discussion of the earliest stages of polyphonic evolution. The period preceding the year 1000 A. D. was truly a _period_ of _fundamental research_ into the underlying principles of melodic and harmonic structure; but so crude and hesitating was the use of what was found that it is certain that polyphonic material was entirely misused until the birth of “measured music” dispelled this darkness by the enlightening influence of Proportion and Form. So many forms of musical growth, such as came in later years, were impossible without the mensural proportion, that is, music written so as to indicate duration, that this initial period gathered but a chaotic mass of musical material which was left undigested and unassimilated until the epoch of the Paris school. =Beginning of Polyphony in Greek Magadizing=.—The music of the Middle Ages has great interest for the historian and the student. It stands between our music and the music of the ancients; it drove its roots deep into the ancient time and extended its branches far into the contemporaneous epoch. It is the struggle between the two elements, the changes foreshadowed and apparent that give such interest to the history of music in the Middle Ages.