Early Baroque music (1600–1654)

The conventional dividing line for the Baroque from the Renaissance begins in Italy, with the composer Claudio Monteverdi (1567–1643), with his creation of a recitative style, and the rise of a form of musical drama called opera. This was part of a self-conscious change in style that was across the arts, most particularly architecture and painting.

Musically the adoption of the figured bass represents a larger change in musical thinking—namely that harmony, that is "taking all of the parts together" was as important as the linear part of polyphony.

Increasingly polyphony and harmony would be seen as two sides of the same idea, with harmonic progressions entering the notion of composing, as well as the use of the tritone as a dissonance. 

Harmonic thinking had existed among particular composers in the previous era, notably Gesualdo, however the Renaissance is felt to give way to the Baroque at the point where it becomes the common vocabulary. 

Some historians of music point to the introduction of the seventh chord without preparation as being the key break with the past. This created the idea that chords, rather than notes, created the sense of closure, which is one of the fundamental ideas of what would much later be called tonality.

Italy formed one of the cornerstones of the new style, as the papacy, besieged by Reformation but with coffers fattened by the immense revenues flowing in from Hapsburg conquest, searched for artistic means to promote faith in the Roman Catholic Church. One of the most important musical centers was Venice, which had both secular and sacred patronage available.

One of the important transitional figures would come out of the drive to revive Catholicism against the growing doctrinal, artistic and social challenge mounted by Protestantism: Giovanni Gabrieli. His work is largely considered to be in the "High Renaissance" style. However, his innovations became to be considered foundational to the new style. Among these are instrumentation (labeling instruments specifically for specific tasks) and the use of dynamics.

Monteverdi became the most visible of a generation of composers who felt that there was a secular means to this "modern" approach to harmony and text, and in 1607 his opera Orfeo would be the landmark which demonstrated the welter of effects and techniques that were associated with this new school, called seconda pratica, to distinguish it from the older style or prima pratica.

Monteverdi was a master of both, producing precisely styled motets that extended the forms of Marenzio and Giaces de Wert. But it is his new style pieces which were to be the most visible changes to the Baroque. These included features which are recognizable even to the end of the baroque period, including use of idiomatic writing, virtuoso flourishes and what Stanley Sadie calls "a thorough going" use of new techniques.

This musical language would prove to be international, as Heinrich Schütz (1585–1672) a German composer who studied in Venice, would adopt it to the liturgical needs of the Elector of Saxony, and serve as the choir master in Dresden.