The harmonic analysis of music using Roman Numerals to express the function of harmony.
In this type of analysis, a key and the Roman Numerals I to IIV are used to display the harmonic function of a passage where the number relates to the scale degree of the harmony.
In a typical Roman Numeral analysis, an uppercase Roman Numeral means the underlying harmony produces a chord that is major while a lowercase Roman Numeral means the underlying harmony produces a chord that is minor. Several other commonly used symbols are o for a diminished chord, + for an augment chord, a ♭, ♮, and ♯ for chords outside the key, and figured bass symbols to notate chord in inversions.
