The Baroque is the earliest period in European music whose music is still widely heard. This is probably because music before this period has an exotic, unfamiliar sound to most modern Western listeners. The music of the middle ages was modal rather than tonal; in other words, it was not based on chords and harmonies in major and minor keys. Most people strongly prefer the musical tradition that they grew up hearing; it “makes sense” to them in a way that unfamiliar traditions do not. In a fundamental way, the Baroque marked the beginning of our familiar tradition.

One of the most obvious differences – a difference that you can hear even if you don’t realize it or can’t explain it – in medieval music is the lack of thirds, the interval that modern (triadic) chords are built from. Medieval music was based instead on the intervals of the perfect fifth and perfect fourth. This gives early music an open, hollow texture and harmonies that are unfamiliar to the modern ear.

It was during the Renaissance that thirds began to be used more often, particularly in the parallel-thirds and parallel-sixths style of fauxbourdon. (Sixths are closely related to thirds in the same way that fourths are closely related to fifths; see about inverted intervals for a full explanation.)

Listen to a phrase accompanied by parallel fifths (medieval-style harmony), and parallel thirds (Baroque-to-modern-style harmony).

The basic sound of the Renaissance was not the parallel harmonies of fauxbourdon, but a complex polyphony of equal, independent (i.e., not moving in parallel) voices. The sound most closely associated with the Baroque kept the independent, contrapuntal voices, but with some important differences.

The most important change, as mentioned above, was the development during this era of tonal harmony. The composers of the mature Baroque were not only using major and minor chords, but were using them in the kinds of chord progressions and with the kinds of cadences that have continued to be used throughout the following centuries to our own times. This is not to say that there were no later changes to the system of harmony developed during the Baroque; the Romantic and early modern eras in particular saw a great deal of experimentation with harmony. The experimentation of the Romantic period expanded the harmonic possibilities inherent within the tonal system; its sound has also strongly influenced subsequent developments, including in popular music. Many modern composers rejected the tonal system altogether, seeking to replace it with other possibilities. Their efforts have been much less influential in other genres, probably since their non-tonal offerings are simply too far outside the range of the familiar for most listeners.

Another development of the Baroque period that is still strongly with us was the rise of the bass line. The voices, or lines, of Renaissance music, and of some Baroque counterpoint, were typically equal in importance. But in much of Baroque music, the various parts were rapidly losing their equality. Instead, the highest line (what we hear as the melody), and the lowest line (the bass) became the most important parts, with the middle lines simply filling in the harmony. In fact, harpsichord players were often expected to improvise an accompaniment given only the bass line with some extra notations. This melody-and-bass-dominated texture, with the bass outlining or strongly implying the harmony, still predominates in most Western music genres and styles.

As mentioned above, there was a great variety of musical forms popular with Baroque composers. Some of these, such as the highly contrapuntal fugues and inventions, are closely associated with this period. Others, including fantasies, variations, suites, sonatas, sinfonias, and concertos, proved more influential, with many major composers using, developing and experimenting with these forms throughout later eras.

The composers of the Classical period were strongly influenced by the ideals of the Enlightenment, which strongly preferred the “natural” over the formal, and egalitarianism over elitism. Concluding that the complex counterpoint of the Baroque was too formal and elitist, they consciously set out to develop a new style, with simpler, slower-moving harmonies and dominating melodies, that was easier for the public to follow and understand. Although counterpoint certainly did not disappear from music, the true equal-voices-style counterpoint, that had been so common in the Renaissance and Baroque, became much rarer. (When independent voices were added to music of the Classical and later periods, they were often clearly subjugated to the main melody.) The simpler texture and harmony of the Classical period produced such a markedly different sound that even the casual listener can easily distinguish the typical Baroque piece from the typical Classical.

And yet, most other elements of Baroque music were not rejected. The most important element that remained was, of course, tonal harmony. The tendency to emphasize the melody and bass lines was, if anything, intensified in the simpler textures of the Classical period. Also, many of the forms and ensembles developed during the Baroque were adopted and developed and expanded in the Classical and later periods.