The Fauxbourdon Tradition

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A Bridge to Figured Bass and The Rule of the Octave.

(Level 9 Exploring Music History)

Welcome to a fascinating area of music history that will help you understand the foundational principles of harmony, specifically how the fauxbourdon tradition, an ancient technique, paved the way for two fundamental concepts in classical music theory: Figured Bass and The Rule of the Octave.

You already know the building blocks, triads and Roman Numerals, but these new concepts will give you a deeper appreciation for how composers and performers in the Baroque and Classical eras organised their music.

Fauxbourdon: The "False Bass"

The term fauxbourdon (French for "false bass") describes a compositional technique that became highly popular in the early 15th century. It was an ingenious method for creating a full, rich sound with only three written voices.

The Fauxbourdon Recipe

In true fauxbourdon style, only two parts were actually written down: the upper voice (the melody) and the lowest voice (the tenor or bass). The third, middle voice was improvised and was sung by reading the upper voice a perfect fourth below the written notes.

This practice guaranteed that the resulting three-voice texture created a series of first-inversion chords, or Ib (using your Roman Numeral knowledge). The harmonic interval between the highest and lowest voice was typically a sixth.

Written Voice	Improvised Voice	Interval Above the Bass (Tenor)	Harmonic Result	Roman Numeral
Upper (Melody)	Middle Voice	A Perfect Fourth below Upper Voice	6th chord	Ib
Lowest (Tenor)	N/A	Lowest Voice is the Actual Bass

The sound of fauxbourdon is characterised by its smooth, mostly stepwise motion and the prevalence of the first-inversion sound.

The Connection to Figured Bass

Figured Bass (or basso continuo) is a shorthand notation used primarily in the Baroque period (c. 1600–1750). The bass line was written out, and small numbers (or "figures") were placed above or below the staff to indicate the required harmony, which the keyboard player (the continuo player) was expected to improvise.

Here is where fauxbourdon provides a valuable introduction:

The Figured Bass of Fauxbourdon

The entire fauxbourdon texture, because it is essentially a chain of Ib chords, can be represented by a single figure: the number 6.

The number '6' in figured bass means: The note a sixth above the bass note must be present in the chord.

Since the Ib is a three-note chord (Root, Third, Sixth), the 6 is shorthand for the full figured bass of a first-inversion triad: 6/3. The '3' (the third above the bass) is often omitted because it is the standard, expected interval.

Chord	Written Roman Numeral	Figured Bass Shorthand
Root Position Triad	I	5/3 (often blank)
First Inversion Triad	Ib	6/3 (the three is not usually shown)
Second Inversion Triad	Ic	6/4

Understanding fauxbourdon is like understanding an extended passage of a '6' in figured bass—a very simple, clear harmonic pattern.

The Rule of the Octave

As you move toward more complex figured bass, you encounter The Rule of the Octave (Regola dell'Ottava), which established how a bass line should be harmonised when it moves by scale degrees. This rule was the foundation for keyboard improvisation during the Baroque era.

How the Rule Works

The Rule of the Octave provides a standard set of figures for harmonising a scale ascending and descending. It ensures smooth voice-leading and logical harmonic motion, often relying heavily on those same first-inversion '6' chords that fauxbourdon loves.

Scale Degree (Bass Note)	Ascending Rule of the Octave Figures	Descending Rule of the Octave Figures
Do - 1	Blank (5/3)	5/3 (Root position)
Re - 2	6/4/3 (a special chord)	6 (First inversion)
Mi - 3	6 (First inversion)	6/4/2 (a special chord)
Fa - 4	6 (First inversion)	6 (First inversion)
Sol - 5	7 (V7 or V)	7 (V7 or V)
La - 6	6/4/2 (a special chord)	6 (First inversion)
Ti - 7	5/3 (Root position)	5/3 (Root position)
Do - 8	5/3 (Root position)	5/3 (Root position)
Bold	Stable points of arrival
Italic	Unstable notes and more mobile

Notice how the '6' (first inversion) figure is the most common harmony used for the inner scale degrees. This preference for first-inversion chords—the core of the fauxbourdon sound—is adopted into the Rule of the Octave to maintain smooth, diatonic voice-leading and avoid too many "root position" leaps in the inner voices.

For further reading, consider looking at the works of Robert O. Gjerdinge on early figured bass practices and the writings of Elam Rotem concerning the history of harmony.

You can also view a digitised copy of a 15th-century fauxbourdon manuscript at https://www.diamm.ac.uk/sources/805/#/images. Below is an example from Wikipedia. This excerpt is from Ave Maris Stella, a Marian Antiphon, arranged by Guillaume Du Fay and transcribed into modern notation. The top and bottom lines are original compositions; the middle line, labeled "fauxbourdon" in the original, mirrors the top line's contours while consistently staying a perfect fourth below. The bottom line is frequently, but not always, a sixth below the top line; it is ornamented and concludes cadences on the octave.

Sheet music with three staves, notes, and lyrics saying "Sumens illud Ave." Black notation on a white background. — *Example of fauxbourdon from Wikipedia. The original can be seen online at* *The Biblioteca Apostolica Vaticana* (Biblioteca Apostolica Vaticana , Vatican City, Vatican, 2024)

Your Next Step

As an intermediate piano student, the best way to understand this connection is to practice harmonising simple scales using the '6' figure.

Try the following exercise in your manuscript book and take the answer to your next lesson.

Write a C-Major scale (ascending and descending) in the bass clef.
Above every note except the tonic 1 and dominant 5, write the figure 6.
Harmonise the bass line by adding two upper notes that complete the Ib chord.
- Hint: The notes must be a third and a sixth above the bass note.

This exercise is your modern-day echo of the fauxbourdon tradition, now applied through the lens of Figured Bass. Like fauxbourdon, this simplified version of the rule relies on imperfect consonances (3, 6) for mobile middle tones and perfect consonances (5, 8) for stable arrival points.

It will give you an intuitive feel for the voice-leading patterns that form the backbone of The Rule of the Octave, preparing you for more complex improvisation and harmonic analysis.

Short-Answer Quiz

Answer the following questions in 2–3 sentences based on the provided text. Write the answers in your music journal and take them to your next lesson for checking.

What is the literal meaning of the term fauxbourdon, and when was this technique most prominent?
In a traditional fauxbourdon arrangement, how many voices were actually written down, and how were they identified?
Describe the specific "recipe" or method used to create the improvised middle voice in fauxbourdon.
What is the primary harmonic characteristic of a piece written in the fauxbourdon style?
What is Figured Bass, and during which musical period was it primarily utilized?
In Figured Bass shorthand, what does the number "6" indicate to a performer?
Define the Rule of the Octave and its role in musical education during the Baroque era.
Why does the Rule of the Octave rely so heavily on the first-inversion '6' chord?
According to the Rule of the Octave charts, which scale degrees serve as "stable points of arrival"?
Describe the structure of Guillaume Du Fay’s Ave Maris Stella as an example of the fauxbourdon tradition.

Glossary of Key Terms

Term	Definition
Basso Continuo	Also known as Figured Bass; a Baroque system of shorthand where figures indicate harmonies to be improvised over a written bass line.
Fauxbourdon	Meaning "false bass"; a 15th-century technique involving three voices, where the middle voice is improvised a fourth below the melody.
Figured Bass	A notation system using small numbers above or below a bass staff to denote intervals and chords relative to the bass note.
First Inversion (Ib)	A triad where the third of the chord is in the bass, resulting in the intervals of a third and a sixth above the bass.
Imperfect Consonance	Intervals such as thirds and sixths that provide a sense of movement or "mobility" in a harmonic progression.
Perfect Consonance	Stable intervals such as the fifth and octave (8th) that represent points of rest or "arrival."
Regola dell'Ottava	Translated as the "Rule of the Octave"; a set of standard harmonies for each degree of a scale, used for teaching improvisation.
Root Position (I)	A triad where the root note is in the bass, typically represented by the figured bass shorthand 5/3 (often left blank).
Tenor	In the context of fauxbourdon, the lowest written voice that provides the foundation for the harmony.
Triad	A three-note chord consisting of a root, a third, and a fifth.

Reference list

Biblioteca Apostolica Vaticana , Vatican City, Vatican (2024). V-CVbav MS Capp. Sist. 15. [online] Diamm.ac.uk. Available at: https://www.diamm.ac.uk/sources/805/#/images [Accessed 12 Feb. 2026]. Page 42r.
Christensen, T., Gjerdingen, R., Sanguinetti, G. and Lutz, R. (2010). Partimento and Continuo Playing in Theory and in Practice. [online] Leuven University Press. doi:https://doi.org/10.2307/j.ctt9qdxdv.
Digital Image Archive of Medieval Music (2019). Digital Image Archive of Medieval Music :: Salve sancta parens (fauxbourdon). [online] Diamm.ac.uk. Available at: https://www.diamm.ac.uk/compositions/6345/ [Accessed 12 Feb. 2026].
Partimenti, F. (n.d.). Partimenti Diminuiti . [online] Monuments of Partimenti website. Available at: https://partimenti.org/partimenti/collections/durante/durante_diminuiti.pdf [Accessed 12 Feb. 2026].
Rotem, E. (2019). Falsobordone. [online] Earlymusicsources.com. Available at: https://www.earlymusicsources.com/youtube/falsobordone [Accessed 7 Oct. 2025].
Tymoczko, D. (n.d.). Music Theory through Performance and Composition. [online] Available at: https://dmitri.mycpanel.princeton.edu/files/pdfs/MUS106handouts.pdf [Accessed 12 Feb. 2026].
Wikipedia Contributors (2025). Fauxbourdon. [online] Wikipedia. Available at: https://en.wikipedia.org/wiki/Fauxbourdon#:~:text=Fauxbourdon%20(also%20fauxbordon%2C%20and%20also%20commonly%20two,mostly%20liturgical%20lyrics%20to%20be%20understood%20clearly. [Accessed 12 Feb. 2026].