Where it all began...

The history of Western music all goes back to the Gregorian chant.  Gregorian chants are named after Pope Gregory I (590-604), who standardized the music used in the Church for each occasion of worship in the Christian calendar.  Originally, the chants were learned by rote, since in those days there was no system in place for writing music down on parchment.  It wasn't until the 9th century or so that singers started making notes in the text corresponding to the shapes of the melody they were supposed to be singing.  These mnemonic aids eventually became the familiar note-and-staff notation we use today.

An early Pie Jesu plainchant survives to this day.  Its original author is unknown, but it was discovered by the scholarly group Altus Pythonibus, and presented in their seminal work In Quaesitio Calicem Sanctum.  The harmony and rhythm for this early piece are quite simple, although the use of percussion makes it an unusual example.

OK.  So perhaps that one was of a bit more recent origin.

A more serious example of a Gregorian chant is the Pange Linga, which was written by Thomas Aquinas (yes, that Thomas Aquinas) in the 13th century.

What is it about Gregorian chants that give them their distinctive sound?

• Gregorian chants are monophonic.  There are no parts to a Gregorian chant; everyone sings the same notes.  (Another way of saying this is that everyone sings in unison.)

• Gregorian chants make heavy use of stepwise motion in the tune.  The difference in pitch between one note and the next is usually pretty small.  Most of the melody consists of half steps and whole steps, with the occasional third thrown in.  There are no big leaps like what you'd hear in the opening lines of "My Bonnie Lies Over the Ocean" or "Chestnuts Roasting on an Open Fire".

If you don't understand what I mean by half steps, whole steps, or thirds, that's OK.  That's something I plan to talk about Very Very Soon (™).

• The rhythm in Gregorian chants tends towards the simple.  Most notes are the same length, with the occasional note being somewhat longer.  There isn't a strong beat.  Although there's a definite pulse to the chant, it's not something you could count 1-2-3-4! to.

What I like about this YouTube video is that you can see all three of these features on the score.  You don't need to be able to read music to see it.  (And Gregorian chants are written in an older form of staff notation anyway!)  One part.  Notes close together on the staff.  And very little notation to indicate any kind of rhythm or meter.

In the meantime, over in France, something else was going on.  A composer by the name of Pérotin (also known as Perotin the Great) was starting something new.  Instead of using just one melody to make music with, Pérotin was adding extra voices on top of the plainchant, or droning under the plainchant, to create harmony.  In addition, we start seeing the development of rhythmic variation.  In Pérotin's Viderunt Omnes, which was written around the year 1200, you can hear the bass singing a series of sustained notes throughout the piece, while the upper voices dance to alternating long and short notes.

What's really interesting is the fact not only does this piece by Pérotin predate the birth of Aquinas by a good quarter century, it's a piece that Aquinas himself probably would have been familiar with!  Aquinas studied theology at the University of Paris from to 1245 to 1248, a stone's throw away from the Notre Dame cathedral, where Pérotin had been working.  Aquinas returned to Paris twice after that, between 1256 and 1259, and then from 1269 to 1272.  So although Aquinas may well have known about Pérotin's work, he chose the older, more traditional form of chant instead.

But then, we see the same thing in pop music today.  Contrast Simon and Garfunkel with Jimi Hendrix.  Or Skrillex with Mumford and Sons.

As time went on, composers purposely borrowed from the plainchant tradition to create new, more complex works.  During the Renaissance, masses were commonly written in which each section of the mass (the Kyrie, Gloria, Credo, Sanctus, Benedictus, and Agnus Dei) took its musical theme material from a Gregorian chant, or, sometimes, a popular song of the day.  This technique is called cantus firmus, or "fixed song".  Renaissance composer Josquin des Prez (1450 - 1521) used this technique in his mass Missa Pange Lingua, which is believed to be the last mass he ever wrote.  Each movement of the mass uses as its theme the Pange Lingua that Aquinas wrote.  Listen to the first movement, the Kyrie, to see what I mean:

The tenor comes in with the Aquinas theme: kyrie eleison.  But the bass is right behind him, ready to give an answer before the tenor gets a chance to finish: kyrie eleison.  The bass' theme isn't exactly the same theme as the tenor's - it's rhythmically similar, but it's transposed quite a bit down and it doesn't seem to go all the way like the tenor line does.  But that's OK.  The soprano comes in with the theme, followed by the alto … and then the bass is back, and then the tenor…

What we see here is an early example of a musical technique called counterpoint.  Counterpoint is a polyphonic technique in which several musical lines, each with its own independent sound and rhythm, interact with each other to form a harmonious whole when played together.  There's a notable German composer from the Baroque period, whose last name begins with B, who was the ultimate master of the art of counterpoint… but of him we will speak later, and with great reverence.

Next up… the plainchant makes a reappearance in the 20th century.