Music theory developed over thousands of years. It was shaped and molded by many great influencers along the way. What follows is a chronological list of the most influential music theorists.
Pythagoras (582–507 BC): According to legend, Pythagoras took a piece of string from a lyre, plucked it, measured its tone and vibration rate, and then cut that string in half and made a new set of measurements. He named the difference between the rate of vibration of the first length of string and the second an octave, and then he went to work breaking the octave up into 12 evenly divided units. Every point around the circle was assigned a pitch value, and each pitch value was exactly 1/12 of an octave higher or lower than the note next to it. This study led him to create the Circle of Fifths, which has been modified and used by millions of musicians even since.
Boethius (480–524 AD): Anicius Manlius Severinus Boethius was a remarkable man who dedicated his short life to studying Greek mathematics, philosophy, history, and music theory. He was the first scholar after Pythagoras to try to connect the pitch of a note with the vibration of sound waves.
Gerbert d’Aurillac/Pope Sylvester II (950–1003): Pope Sylvester II resurrected an instrument from ancient Greece called a monochord for his students, from which it was possible to calculate musical vibrations. He was the first European after the fall of Rome to come up with a standard notation of notes in tones and semitones (half steps) and eventually designed and built the first hydraulically powered musical organ.
Guido D’Arezzo (990–1040): Guido D’Arrezo was a Benedictine monk who designed his own musical staff for teaching Gregorian chants and eventually created solfège, a vocal scale system that used the six tones of do, re, mi, fa, so, and la. Later, when the diatonic scale was combined with the “Guidonian Scale,” as it’s sometimes called, the ti sound finished the octave.
Nicola Vicentino (1511–1576): Nicola Vicentino was an Italian music theorist of the Renaissance period whose experiments with keyboard design and equal-temperament tuning rival those of many 20th century theorists. To prove the inadequacies of the diatonic scale, he designed and built his own microtonal keyboard that matched a music scale of his own devising, called the 31-tone archicembalo.
Christiaan Huygens (1629–1695): Christiaan Huygens was a mathematician, astronomer, physicist, and music theorist who worked out the use of logarithms in the calculation of string lengths and interval sizes, and helped rework the Circle of Fifths so that 12 tones could finally build a true octave.
Arnold Schoenberg (1874–1951): Throughout his career, Schoenberg’s work featured many firsts. His symphonic poem, “Pelleas and Melisande,” featured the first known recorded trombone glissando. His opera, “Moses und Aron,” was the first one to draw on both his experiments with the 12-tone series and on atonality. His most massive composition, “Gurrelieder,” combined orchestra, vocals, and a narrator — over 400 performers were required for the original performance of the piece.
Harry Partch (1901–1974): Partch devoted his entire life to producing sounds found only in microtonal scales — the tones found between the notes used on the piano keys, and devised complex theories of intonation and performances, and even instruments, to accompany them, including a 43-tone scale, with which he created most of his compositions.
Karlheinz Stockhausen (1928–2007): Stockhausen is responsible for polyvalent form in music, in which a piece of music can be read upside down, from left to right, or from right to left. Or, if multiple pages are incorporated in a composition in this form, the pages can be played in any order the performer wishes.
Robert Moog (1934–2005): Although no one knows for sure who built the first fretted guitar or who truly designed the first real keyboard, music historians do know who created the first pitch-proper, commercially available synthesizer: Robert Moog. He’s widely recognized as the father of the synthesizer keyboard, and his instrument revolutionized the sound of pop and classical music from the day the instrument hit the streets in 1966.