I. Fundamentals
Roman Numerals
Samuel Brady and Kris Shaffer
Key Takeaways
- Roman numeral analysis is a system of chord labels that contextualize a chord in relation to the overall key of a piece.
- The number represented in the Roman numeral corresponds to the scale degree of the chord’s root.
- If the chord has a seventh, a superscript seven (7) is added to the Roman numeral.
- The quality of a chord is also indicated in Roman numeral analysis:
- Chords with a major third above the root (major, augmented) uses a capital Roman numeral.
- Chords with a minor third above the root (minor, diminished, half-diminished) use a lowercase Roman numeral.
- Special symbols are added for augmented (+), diminished (o), and half-diminished (ø) chords.
Musicians use Roman numerals to identify chords within the context of key signatures. Roman numerals identify the scale degree of the chord’s root ( ). Because Roman numerals are based on scale degrees rather than specific pitch names, they are useful for understanding how harmonies function similarly in different keys.
| Scale degree | Uppercase Roman Numeral | Lowercase Roman Numeral |
|---|---|---|
| 1̂ | I | i |
| 2̂ | II | ii |
| 3̂ | III | iii |
| 4̂ | IV | iv |
| 5̂ | V | v |
| 6̂ | VI | vi |
| 7̂ | VII | vii |
To type uppercase Roman numerals, use the uppercase Latin alphabet letters “I” and “V”; likewise, for lowercase Roman numerals, type the lowercase “i” and “v.”[1] Handwritten uppercase Roman numerals have horizontal bars across the top and bottom of the numeral, in order to further distinguish between uppercase and lowercase ( ). There is no such difference with lowercase Roman numerals.
Roman Numerals and Quality
In addition to showing the chord root, Roman numerals may indicate quality of the chord ([2] Uppercase Roman numerals denote major triads, and lowercase Roman numerals denote minor triads. For example, in a major key, a chord built on the first scale degree, [latex]\hat1[/latex] or do, is identified as “I,” a chord built on the second scale degree, [latex]\hat2[/latex] or re, is identified by the lowercase Roman numeral “ii,” and so on. Lowercase Roman numerals followed by a superscript “o” (such as viio) represent diminished triads. Uppercase Roman numerals followed by a + sign (such as V+) represent augmented triads.
).
| Triad quality | Roman numeral characteristics | Example |
|---|---|---|
| major | uppercase | V |
| minor | lowercase | ii |
| augmented | uppercase with + | V+ |
| diminished | lowercase with o | viio |
Just as scale degrees and solfège are the same across keys, so are Roman numerals. shows the Roman numerals for the diatonic triads of G major and G minor as an example, but the same Roman numerals would be used regardless of which pitch is the tonic. The solfège and scale degree of the roots are also labeled—note the correspondence between these and the Roman numerals.
As discussed in previous chapters, if the leading tone is raised in minor, the chord quality change