Timeline
Theory did not fall from the sky: every idea on this site was said by someone, at some point, for a reason. Here are those moments, from Pythagoras to bossa nova, and the topics where each idea is explained today.
c. 500 BC
Pythagoras and the ratios of strings
Tradition credits Pythagoras with the discovery that consonant intervals correspond to simple ratios between string lengths: the octave at 2:1, the fifth at 3:2, the fourth at 4:3. Stacking fifths by those ratios produces the Pythagorean scale, and it does not close the circle: twelve fifths overshoot seven octaves by a small excess, the Pythagorean comma, which two thousand years of temperaments would try to distribute.
Read: Consonance and dissonance, Circle of fifths, Enharmonic equivalence.
c. 1025
Guido d'Arezzo and the staff
The monk Guido d'Arezzo systematises notation on lines, with one line fixed by a letter — the clef — and teaches singers to read by the syllables ut, re, mi, fa, sol, la, taken from a hymn. It is the origin of the staff still in use and of the note names in the Latin languages.
Read: The staff, Clef, Scale degrees.
c. 1320
Ars Nova and mensural notation
Philippe de Vitry and the theorists of the Ars Nova give note shapes fixed proportional durations and admit binary division alongside ternary. Notation is born in which each shape is worth a fraction of the one before, and with it the bar as a grouping of beats.
Read: Time signature, Note values and rests, Tempo.
1558
Zarlino and the triad
In Le istitutioni harmoniche, Gioseffo Zarlino treats the third as a full consonance and describes the three-note chord with a major or minor third as the unit of harmony, over just-intonation ratios. It is the first theory in which the triad, and not the interval, is the object.
Read: Triads, Consonance and dissonance, Relative and parallel keys.
c. 1600
Figured bass and the chord symbol
The Baroque practice of writing only the bass, with numbers indicating the intervals to play above it, is the first chord symbol: a notation of chords by abbreviation, read by whoever accompanies. Inversions take their names from the numbers that describe them, and the idea that a chord is a set of notes over a bass takes hold.
Read: Chord symbols, Chord inversions, Voice leading.
1691–1722
Werckmeister, Bach and temperament
Andreas Werckmeister publishes temperaments that distribute the comma so as to make every key tolerable; in 1722 Bach writes The Well-Tempered Clavier, a prelude and fugue in each of the twenty-four keys, the demonstration that the circle of fifths closes and the key signature can go anywhere.
Read: Key signatures, Circle of fifths, Enharmonic equivalence, Modulation.
1722
Rameau and the fundamental bass
In the Traité de l'harmonie, Jean-Philippe Rameau proposes that every chord has a root, even when inverted, and that harmony moves by a fundamental bass leaping in fifths. Dominant and subdominant get their names, the cadence gets its explanation, and modern harmonic analysis begins here.
Read: Harmonic function, Chord inversions, Cadences, Circle of fifths.
1725
Fux and species counterpoint
Johann Joseph Fux publishes Gradus ad Parnassum, the method of counterpoint in five species that Haydn, Mozart and Beethoven would study. The rules of voice leading — common tones held, movement by step, parallel fifths and octaves avoided — are formulated there as exercise.
Read: Voice leading, Non-chord tones, Consonance and dissonance.
1815
Maelzel's metronome
Johann Maelzel patents the metronome, and Beethoven is among the first to mark tempos in beats per minute. The Italian word stops being the only indication of speed, and tempo becomes a number.
Read: Tempo, The measure.
1880–1935
Chiquinha Gonzaga, Ernesto Nazareth and choro
Choro is born in Rio de Janeiro from the meeting of the European polka and waltz with African syncopation. Chiquinha Gonzaga and Ernesto Nazareth write for piano the pieces that fix the genre, with the bass in motion, the passing diminished chord, modulation between sections, and the three-part form.
Read: Brazilian rhythms, Syncopation, Diminished chords, Musical form.
1893
Riemann and tonal functions
Hugo Riemann reduces the seven degrees to three functions — tonic, subdominant and dominant — and explains the rest as substitutes for them. It is the functional theory that Brazilian popular harmony adopts, and the origin of the idea that chords sharing notes can stand in for one another.
Read: Harmonic function, Roman numeral analysis, Modal interchange.
1917–1930
Urban samba
The recording of Pelo Telefone in 1917 and the samba of Estácio in the 1920s fix urban samba: the surdo on the second beat, the semiquaver–quaver–semiquaver cell, and the groove written in two-four and felt in displaced sixteenths.
Read: Syncopation, Brazilian rhythms, Metric accent.
1920s–1940s
Jazz and the harmony of extensions
From New Orleans jazz to bebop, popular harmony takes seventh chords as the norm, the II–V–I as a cell, extensions and alterations over the dominant, and tritone substitution. It is the chord vocabulary that the Brazilian chord chart would inherit through bossa nova.
Read: The II-V-I, Extended chords, Tritone substitution, Altered dominants, Turnaround.
1946
Luiz Gonzaga and baião
Luiz Gonzaga and Humberto Teixeira record Baião, and the rhythm of the Northeast, accented on the first beat and the last quaver, enters radio music. The melody of baião lives in the Mixolydian mode, with its lowered seventh degree, which major functional harmony does not explain and the modes do.
Read: Brazilian rhythms, Church modes, Syncopation.
1958
João Gilberto, Tom Jobim and bossa nova
Chega de Saudade, recorded by João Gilberto in 1958, joins the guitar's beat — a samba syncopation reduced to the right hand — with the harmony of extensions from jazz: sixth chords with a ninth, borrowings from the parallel minor, chains of II–V–I, a descending chromatic bass. It is the repertoire this site uses as an example in nearly every topic on harmony.
Read: Sixth chords, Extended chords, Modal interchange, Tritone substitution, Syncopation.
1959
Kind of Blue and modal jazz
Miles Davis records Kind of Blue, in which improvisation is organised by modes over chords lasting whole bars, rather than by quick cadences. The mode comes to be thought of through the chord that sustains it, and the pentatonic and the Dorian become the vocabulary of the modern solo.
Read: Church modes, Pentatonic scales, Harmonic rhythm.
1980s–1990s
The songbooks and the standardised chord symbol
Almir Chediak's songbooks fix a consistent chord-symbol spelling for MPB, with extensions written out and inversions with a slash, and make reading a chart the way into harmony for a generation of guitarists. The chord symbol this site reads and verifies is, in large part, that one.
Read: Chord symbols, Extended chords, Chord inversions.
