Pop Music Theory

Lessons

23: Roman Numeral Chords

Lesson 23: Roman Numeral Chords

You learned how we can play a melody in any key in Lesson 22: Keys. And, we can show a melody in all keys at once by writing its notes as scale degrees (numbers) instead of actual pitch names.

This lesson shows how we can do the same thing with chords, by using Roman numeral chord symbols. To understand this lesson, you need to know your major scales and minor triads, so review Lesson 16: Minor Triads and Lesson 18: Major Scale 1-8 if you need to.

You also need to know Roman numerals, but just the numbers 1 through 6:

Arabic numerals:1 23 45 6
Roman numerals:I IIIIIIVVVI

A Roman numeral chord symbol is like a regular chord symbol except that we use a Roman numeral instead of a pitch name. The Roman numeral is the scale degree of the key the song is in which matches the chord's root.

A few "question and answer" examples are probably easier to understand than that definition:

Q: A song in the key of C uses a Dm ("D minor") chord. What is the chord's Roman symbol?

A: The pitch D (the chord's root) is scale degree 2 of a C major scale (the song's key). So the Roman numeral is II (for scale degree 2), and the complete answer is IIm ("two minor", which is just the original chord symbol, "Dm", replacing the "D" with "II").

Q: What is the IV chord in the key of E♭?

A: IV means the "four major" chord, so the chord's root will be scale degree 4 of an E♭ major scale (because we're in the key of E♭). The 4th note of an E♭ major scale is A♭, so the answer (the chord symbol) is just A♭ (an "A-flat major chord").

When you understand the examples above, you can start using Roman numeral chords in Lesson 24: Diatonic Triads.

Pop vs. classical Roman systems

There is a "classical" Roman-numeral-analysis system, a couple of hundred years old, which is not the system I use in these lessons. Instead, I use what I call the "Berklee system" (because I learned it at Berklee College of Music), which works better for modern pop chord progressions. If you happen to know the classical system already, here are a couple of the differences:
  • The classical system uses lower-case numerals (e.g. ii, iii) for minor chords. The Berklee system always uses upper-case numerals, along with the usual symbol for the chord's type (e.g. "m" for minor).
  • When the song's in a minor key, the classical system uses the key's minor scale for the Roman numerals. For example, in the key of C minor, the III chord's root is the 3rd note of a C minor scale, not a C major scale. (If you don't know minor keys and minor scales yet, don't worry about it; we'll cover this when we need to.)

    The Berklee system doesn't do this; the Berklee system always uses the key's major scale for the Roman numerals. This is much simpler when a song mixes the major and minor keys together, which pop music sometimes does.


Lessons

1: Introduction
2: Pitch & Keyboard
3: Pitch Names
4: Letters Game
5: Sharps & Flats
6: Half-Steps
7: Whole-Steps
8: Steps Game
9: Scales
10: Major Scale 1-2-3
11: Major 1-2-3 Games
12: Major Scale 1-5
13: Major 1-5 Games
14: Chords: Major Triads
15: Major Triad Games
16: Minor Triads
17: Minor Triad Games
18: Major Scale 1-8
19: Major Scale Games
20: Scales Above 8
21: What Next
22: Keys
23: Roman Numeral Chords
24: Diatonic Triads
25: Treble Staff
26: Pitch & Frequency

© 2017 Conrad Albrecht. All rights reserved.