In a scale, the positioning of tones and semitones relative to one another determines what the "mode" of the music is. The main modes that have survived are the major and minor modes, but others are still used today. Each mode was said to create a particular mood and have a particular influence on the listener. Start your scale on any white key on the piano and you have a mode at your fingertips.
Also called plainsong, is a form of medieval church music that involves chanting; it emerged around 100 A.D. Plainchant doesn't use any instrumental accompaniment. It was the only type of music allowed in Christian churches, as music should make a listener receptive to spiritual thoughts and reflections. This was why the melody was kept pure and unaccompanied.
Several lines of music which are independently coherent but which sound well together is polyphony. The term is usually used to refer to music of the late Middle Ages and Renaissance.
Baroque forms such as the fugue, which are indeed polyphonic but are usually described instead as contrapuntal. There were strict rules governing the art of fugue.
Sonata Form is not to be confused with the sonata, which is generally a piece of music in several movements for a solo instrument accompanied, usually, by a keyboard.
Sonata form is a way of structuring a movement of music and it developed over time, reaching its fullfilment in the works of Joseph Haydn (1732-1809). Its outline is as follows: a first theme or subject in the main key is announced; a second subject is then introduced in a different key. There then follows a development section in which the themes are explored and played with, perhaps passing through several key changes and variations. After the development, the two original subjects are repeated, both now in the home key, before a tail-piece or "coda" brings the movement to a close.
The effect of sonata form is to establish a home base then to take the listener on a journey, finally returning home after a musical adventure.
Opera is perhaps the culmination of music in the sense that it is integrated with every other art form. In the works of Richard Wagner his stated aim was a "total art". In opera we can see before us the archetypes of humanity acting out their roles and in Wagner's operas, the gods themselves doing just that.
Music As Landscape
Since the end of the 19th century, the idea of a piece of music as a journey has been superseded by several different approaches, each of which may create a musical landscape. Richard Strauss's tone poems, such as "Also Sprach Zarathustra", are cited as the beginning of this musical revolution. Other landscape forms include, for example, the impressionist music of Debussy and ambient music which creates a particular mood, capturing and holding the listener in a meditative state.
A harmonious chord is created by sounding three (or more) notes simultaneously. These are the root note, the note which is the interval of a third above it and the note a third above this.
To make music comprehensible the idea of chord progressions has developed. It is a joke that pop groups only use three chords in their twelve-bar blues music, but in fact those same three chords were universally employed in classical music - with, of course, others.
One notable chord progression that has been used time and again is the "cycle of fifths" which starts from any beginning chord. The chord root then moves up the interval of a fourth to become the root of a new chord, then down a fifth, up a fourth, down a fifth and so on, until the original chord comes around again.
When you have heard this sequence and know what it is, you will recognise it as something familiar and satisfying. The "folia" was another form involving a specific chord progression that Baroque composers loved to play around with - a musical dance to the death. Over the course of three centuries, more than 150 composers have used it in their works.