Roman Numerals

Roman numeral analysis labels chords by the scale degree of their root. Uppercase numerals (I, II, IV, V, VI) indicate major-quality chords; lowercase (ii, iii, iv, vi, vii) indicate minor; a degree symbol (°) marks diminished; a plus sign (+) marks augmented. The numeral alone specifies a triad; a superscript 7 adds a seventh chord (e.g., V7, ii7, viiø7).

The power of Roman numeral analysis is that it reveals harmonic function independent of key. I always functions as tonic, V as dominant, IV and ii as predominant, regardless of whether the key is C major or F♯ minor. This abstraction allows musicians to recognize recurring harmonic patterns — cadences, progressions, sequences — and apply them across all keys.

Inversion is incorporated into Roman numeral notation using figured bass superscripts. I⁶ means the tonic triad in first inversion; a triad in second inversion takes a 6/4 figure — for example the cadential six-four, written I⁶₄, a tonic sonority sounding over a dominant (5̂) bass. For seventh chords, V⁶₅ is V7 in first inversion, V⁴₃ is second inversion, and V⁴₂ is third inversion. Combined with the key label (e.g., "in G major" or "in d minor"), a Roman numeral analysis gives a complete harmonic reading of a passage.