The conventional dividing line for the Baroque from the Renaissance begins in Italy, with the Florentine Camerata, a group of academics who met informally in Florence in the palace of Count Giovanni de' Bardi to discuss arts, as well as the sciences. Concerning music, their ideals were based on their perception of ancient Greek musical drama, in which the declamation of the text was of utmost importance. As such, they rejected the complex polyphony of the late renaissance and desired a form of musical drama which consisted primarily of a simple solo melody, with a basic accompaniment. The early realizations of these ideas, including Jacopo Peri's Dafne and L'Euridice, marked the beginning of opera.
Musically, the adoption of the figured bass represents a larger change in musical thinking—namely that harm, that is "taking all of the parts together" was as important as the linear part of polyphony. Increasingly, polyphony and harmony were 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 Carlo 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 came to be known as 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 Habsburg 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.
Giovanni Gabrieli became one of the important transitional figures in the emergence of the new style, although his work is largely considered to be in the "High Renaissance" manner. However, his innovations were foundational to the new style. A these are instrumentation (labeling instruments specifically for specific tasks) and the use of dynamics.
The demands of religion were also to make the text of sacred works clearer, and hence there was pressure to move away from the densely layered polyphony of the Renaissance, to lines which put the words front and center, or had a more limited range of imitation. This created the demand for a more intricate weaving of the vocal line against backdrop, or homophony.
Claudio 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 L'Orfeo became the landmark which demonstrated the array 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 madrigals that extended the forms of Luca Marenzio and Giaches de Wert. But it is his pieces in the new style which became the most influential. These included features which are recognizable even to the end of the baroque period, including use of idiomatic writing, virtuoso flourishes, and the use of new techniques.
This musical language proved to be international, as Heinrich Schütz, a German composer who studied in Venice under both Gabrieli and later Monteverdi, used it to the liturgical needs of the Elector of Saxony and served as the choir master in ecreaon.