The distinguishing characteristics of Baroque music from the earlier Renaissance music is the importance of the expression of emotions, and in vocal music, the clarity of the text.

Baroque times saw a renewed interest in ancient classical culture, especially classical Greek philosophy. One of the most important lines of thought culled from the classics was "The Doctrine of the Affections", which stated that there were specific "vapors" inside the body that, in turn, gave rise to specific emotions. These affections could be roused by like things in the outside world, such as musical devices. This, in conjunction with the study of ancient rhetoric, gave rise to a quite codified language of emotional expression in music. This means of expression stands in sharp contrast against the music of the Renaissance, which was not looking to explicitly express specific emotions, but to spiritually transcend earthly languages.

Whereas many expressive vocal pieces were written earlier, the text would be set in dense polyphony (see Giovanni Pierluigi da Palestrina), as compared to the more characteristically Baroque homophonic settings of Claudio Monteverdi's later madrigals. These textual settings often employed the technique of text painting, or mimicking the subject of the text with musical techniques. For example, the word "pain" may be set in a harsh dissonance, or a passage about ascension into heaven would be set in a rising melody.