authentic mode

An authentic mode in music is a church mode, such as Phrygian or Mixolydian, that spans approximately an octave above its final note. These modes are part of a larger system of church modes, which are scalar arrangements of tones used in medieval music.12

Originally, there were eight church modes, derived from ancient Greek musical concepts. These modes were classified as either authentic or plagal. Authentic modes begin and end on the same note, called the finalis, while plagal modes range from a fourth below to a fifth above the finalis. Each mode also has a characteristic recitation tone, known as the tenor or confinalis.2

Over time, the system evolved, with the addition of new modes and the eventual shift towards the modern major and minor scales. However, church modes continue to be relevant in the analysis of folk music and have seen a revival in contemporary compositions.3