Madrigals are a form of vocal polyphony that is unaccompanied by instruments for a varying number of voices, ranging from 2 to 8. Unlike the strophic songs of the time, most madrigals are composed using high-quality poetry, without strophic repetition or refrain. The music is descriptive: it reflects the meaning of the text and expresses the sentiments of each line. In the Fifth Book of Madrigals (1605), Monteverdi made his first comparison between the new style or “seconda prattica” (associated in his preface to the “perfection of modern music”) and the old style or “prima prattica”. The latter was characterized by strict observance of the rules of sixteenth-century counterpoint, as they were taught by Gioseffo Zarlino.