How did Claudio Monteverdi help move music from the Renaissance into the Baroque period?

Claudio Monteverdi was a pivotal figure in the transition from the Renaissance to the Baroque period by bridging traditional polyphony with the emerging modern style.1

He famously identified two musical "practices":
* Prima pratica: The older, traditional style of pure polyphony, exemplified by composers like Giovanni Palestrina, where music remained supreme.1
* Seconda pratica: A modern style that prioritized the emotional expression of the text, often utilizing intense dissonance to "move the whole man," even if it meant breaking conventional rules.1

Monteverdi’s influence was profound in several areas:
* Opera: With his first opera, Orfeo (1607), he expanded the genre beyond simple recitative by incorporating dramatic unity, varied instrumental sonorities, and musical climaxes.12
* Vocal Music: He adapted the monodic style—which favored accompanied solo song over dense counterpoint—into his later madrigals and sacred works, such as his 1610 vespers, which blended traditional plainsong with modern operatic expression.134

By successfully integrating these two practices, Monteverdi helped establish the foundations for the Baroque era's dramatic and expressive musical language.1