In music theory, an augmented sixth chord contains the interval of an augmented sixth, usually above its bass tone. This chord has its origins in the Renaissance,[2] was further developed in the Baroque, and became a distinctive part of the musical style of the Classical and Romantic periods.[3]
Conventionally used with a predominant function (resolving to the dominant), the three most common types of augmented sixth chords are usually called the Italian sixth, the French sixth, and the German sixth.