Authentic cadence
In Western musical theory, a cadence (Latin cadentia, "a falling") is "a melodic or harmonic configuration that creates a sense of resolution [finality or pause]." A harmonic cadence is a progression of (at least) two chords that concludes a phrase, section, or piece of music. A rhythmic cadence is a characteristic rhythmic pattern that indicates the end of a phrase. A cadence is labeled more or less "weak" or "strong" depending on its sense of finality. While cadences are usually classified by specific chord or melodic progressions, the use of such progressions does not necessarily constitute a cadence—there must be a sense of closure, as at the end of a phrase. Harmonic rhythm plays an important part in determining where a cadence occurs.
Cadences are strong indicators of the tonic or central pitch of a passage or piece.Edward Lowinsky proposed that the cadence was the "cradle of tonality."
In music of the common practice period, cadences are divided into four types according to their harmonic progression: authentic, plagal, half, and deceptive. Typically, phrases end on authentic or half cadences, and the terms plagal and deceptive refer to motion that avoids or follows a phrase-ending cadence. Each cadence can be described using the Roman numeral system of naming chords:
One of the most striking uses of this cadence is in the A minor section at the end of the exposition in the First Movement of Brahms' Third Symphony. The music progresses to an implied E minor dominant (B7) with a rapid chromatic scale upwards, but suddenly sidesteps to C major. The same device is used again in the recapitulation; this time the sidestep is—as one would expect—to F major, the tonic key of the whole Symphony.
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