Roman Numerals

Did music theory begin in Rome? History doesn’t say if it does or not but one thing is for sure: Without Roman Numerals, music theorists would have to totally redesign their system of analyzing music. Let’s take a look at how Roman Numerals are used by music theorists.

First, the good news. If you find the whole system of roman numerals confusing, in music theory you will only use a few of these. As long as you can figure out the numbers 1 through 7, that’s all you will need for music.

First, let’s think about our triads. In a traditional scale, there are 7 different diatonic chords, each one of these based on one of the scale degrees. Let’s assume that we’re in the key of C Major. The C-E-G chord which is built on the first scale degree is called the “I” (Roman numeral) chord. (The “one” chord)

The next chord, D-F-A, is the “ii” chord because it’s based on the 2^nd scale degree. The next chord, E-G-B is built on the third scale degree and it is referred to as the “iii” chord. Are you getting the pattern? This part of traditional analysis is the easiest part.

Now, you might be wondering why the “I” is an upper case roman numeral while the “ii” and “iii” roman numerals were written in lower case. The reason for this is because the “I” chord is a major chord while the “ii” and “iii” chords are minor chords. Always use uppercase for major chords and lowercase for minor chords. There are other types of chords, like augmented and diminished which we’ll save for a more advanced lesson.

Now that we know how to identify chords, is it that simple? Of course not! Remember those chord inversions? If a chord is root position, we leave the Roman numeral as is. If the chord is in first position, we put a “6” in superscript next to the Roman numeral. (Just like in math when you notate something is squared)

If a chord is in second inversion, we notate it by placing a 6/4 (fraction without the line in superscript) next to it. There are other indications of inversion for more extended chords but we won’t worry about that just yet.

Remember that Roman numerals are based on the key that you declare. Because it’s sometimes difficult to tell which key the composer is writing in, the music theorist must state which key he or she is basing their analysis. This is done by playing an indication in the music such as “C:”. This indicates that all of the roman numerals are based on the key of C.

Of course there are many more symbols that are used in analysis of this type but as far as roman numerals go, Roman numerals are actually pretty easy.