Authentic Cadence

Overview

An authentic cadence is a harmonic formula that resolves from the dominant harmony (V) to the tonic (I) in a major or minor key. When the tonic appears in root position and the highest voice ends on the tonic note, the cadence is classified as a perfect authentic cadence (PAC); otherwise it is an imperfect authentic cadence (IAC). Both types provide a strong sense of closure, but the PAC is considered the most conclusive in common‑practice harmony.

Authentic cadences are a cornerstone of tonal music, structuring phrases, sections, and entire movements. They are taught early in music theory curricula because they illustrate fundamental principles of voice leading, chord function, and tonal stability.

History / Origin

The term “cadence” derives from the Latin *cadere*, meaning “to fall” or “to come to rest.” The specific concept of an authentic cadence emerged during the Baroque era, when composers such as Johann Sebastian Bach codified functional harmony. The distinction between perfect and imperfect authentic cadences was later formalised by 18th‑century theorists like Johann Joseph Fux in his treatise *Gradus ad Parnassum* (1725), which became a primary textbook for teaching counterpoint and harmonic progression.

How It’s Used

Authentic cadences appear across a wide range of Western music genres, from classical symphonies and sonatas to jazz standards and popular song forms. In classical scores they are notated with a V–I progression, often preceded by a dominant preparation such as a ii–V or a secondary dominant. In jazz, the same functional movement may be voiced with extended or altered chords (e.g., V7♭9–IΔ). In popular music, the cadence frequently underlies the final chord of a chorus or the ending of a song, sometimes simplified to a I–V–I loop.

Why It Matters

For composers and performers, the authentic cadence signals the end of a musical thought, enabling clear phrase delineation and emotional resolution. Listeners intuitively recognize the V–I motion as a cue that a section is concluding, which contributes to the sense of direction and satisfaction in tonal music. Iconic examples include the final bars of Beethoven’s Symphony No. 5, the closing phrase of Mozart’s *Eine kleine Nachtmusik*, and the ending of the pop song “Let It Be” by The Beatles, all of which employ perfect authentic cadences.

Common Misconceptions

Because several types of cadences share similar chord symbols, they are often confused. The following points clarify frequent misunderstandings.

• Misconception: Any V–I progression is a perfect authentic cadence.
  Correction: A perfect authentic cadence requires the tonic chord to be in root position and the highest voice to end on the tonic pitch; otherwise it is imperfect.
• Misconception: An authentic cadence always uses a major dominant chord.
  Correction: In minor keys the dominant is typically a major or dominant‑seventh chord built on the raised leading tone, still functioning as V.
• Misconception: A half cadence is simply a weaker authentic cadence.
  Correction: A half cadence ends on the dominant (V) and creates an open, unresolved feeling, unlike an authentic cadence which resolves to the tonic.