<P> Of all the composers of madrigals of the late 16th century, none was as central a figure as Claudio Monteverdi, who was often credited as the principal actor in the transition from Renaissance music to Baroque music . In his long career, he wrote nine books of madrigals, which showed the transition from the late 16th - century polyphonic style to the monodic and concertato style, accompanied by basso continuo, of the early Baroque . </P> <P> As expressive as Gesualdo, he avoided the extremes of chromaticism employed by that composer and instead focused on the dramatic possibilities inherent in the form . His fifth and sixth books include not only polyphonic madrigals for equal voices in the manner of the late 16th century, but also madrigals with parts for solo voice accompanied by continuo; additionally these works make use of unprepared dissonances and recitative - like passages, foreshadowing the eventual absorption of the solo madrigal into the aria . These madrigals also show the influence of monody, developing at the same time: Manfred Bukofzer called the development of the recitative - like' stile rappresentativo' around 1600 as "the most important turning point in the entire history of music ." </P> <P> To Monteverdi, the words must be "the mistress of the harmony", and he explained this doctrine in his preface to his Fifth Book of Madrigals with his coinage of the term seconda pratica, in response to the fierce criticism of Giovanni Artusi, who defended the polyphonic style of the 16th century with its controlled dissonance and equal voice parts, and attacked the "barbaric" new style . </P> <P> During the first decade of the 17th century the madrigal moved away from the old ideal of an a cappella vocal composition for equally balanced voices, into a piece for one or more voices with instrumental accompaniment . The soprano and bass line became more important to the texture than the inner voices, if they existed at all as independent parts; functional tonality began to develop; composers treated dissonance more freely than before; and dramatic contrasts between groupings of voices and instruments became increasingly common . In the 17th century madrigal, two separate trends can be identified: the solo madrigal, which involved a solo voice with basso continuo, and madrigals for two or more voices, also with basso continuo . In addition, some composers continued to write ensemble madrigals in the older style, especially in England . While the harmonic and dramatic changes in the madrigal around 1600 may seem abrupt, the addition of instruments was not a new development . Instrumental performance of madrigals had already been widespread for much of the 16th century, either in arrangements or in performances mixed with singers . As madrigals had originally been largely designed for performance by groups of talented amateurs, without a passive audience, instruments were also commonly used to fill in for missing parts . Instrumentation during the period was rarely specified; indeed Monteverdi indicated in his fifth and sixth book of madrigals that the basso seguente, the instrumental bass part, was optional in the ensemble madrigals . The most commonly used instruments for playing the bass line and filling in any inner parts, at this time, were the lute, theorbo (chitarrone), and harpsichord . </P>

Instrumental music became as important as vocal music for the first time in the