Gregorian chant was the official music of the Christian church for several hundred years. Chant consists of one melodic line that is sung by a soloist or a group of people. Each note of the melody is the same length except for the last note of a phrase. No instruments were played and there were no harmonies in the vocal parts. As you can imagine, after a few hundred years of this practice, musicians were ready to move onward.
In the late twelfth century, Master Leoninus of Notre Dame of Paris added a separate musical line to a Gregorian chant. The resulting combination of two independent melodies in early church music is called organum — the first example of polyphony. Leoninus’s contribution to Western art music was enormous and opened the door to many creative developments in composition.

Polyphonic music involves two or more independent musical lines that are played at the same time. Another name for polyphony is counterpoint which literally means “point against point,” or in musical terms “note against note.”

There are two types of counterpoint — imitative and free. Imitative counterpoint, like the name suggests, features one line that is imitated by another. When the imitating part copies the first statement exactly it is called a canon. A simple version of a canon is a round. Think back to when you sang Row, Row, Row Your Boat, which is a perfect example of a round. In performing this piece, the first group sings “Row, row, row, your boat, gently down the stream,” at which point the second group enters and sings the exact same words with the exact same pitches.

There can be any number of entrances in imitative counterpoint. Just for fun, organize some of your friends or co-workers and sing Row, Row, Row Your Boat in a round, and form as many melodic groups as possible. For added contrapuntal interest, have each group enter after the word “boat.” Also, if you’re up for a real musical challenge, have the imitating groups start their melodies on different pitches than the first group that sings. The result will still be imitative counterpoint, but it will no longer be a round or canon.

On the opposite end of the spectrum from imitative counterpoint is free counterpoint, which occurs when there is no imitation involved in the polyphony. If one person sings Row, Row, Row while another person sings Twinkle, Twinkle, Little Star there will be two separate melodic lines performed simultaneously. This new composition is an example of free counterpoint.

After Leoninus’s development of organum, counterpoint quickly became all the rage in the musical world. In the renaissance, the Mass, motet, and madrigal were almost entirely polyphonic, with as many as five separate vocal lines being sung at once. The baroque era brought a significant change to musical texture. The melody was the most important part of the music and composers found that counterpoint obscured that melody. Therefore, they composed in a homophonic style in which the melody is accompanied by chords that do not draw the listener’s attention away from the solo part. By the late baroque era though, counterpoint was gaining in importance, especially in the music of Bach who was perhaps the greatest master of counterpoint ever.

The classical and romantic eras saw a return to music that was primarily homophonic. That is not to say that counterpoint was no longer written — most composers included some form of counterpoint in their works. The twentieth century has seen every possible type of musical texture and many composers have written strictly contrapuntal pieces.