Dorian mode

Medieval Dorian mode[edit]

The early Byzantine church developed a system of eight musical modes (the octoechos), which served as a model for medieval European chant theorists when they developed their own modal classification system starting in the 9th century.^[3] The success of the Western synthesis of this system with elements from the fourth book of De institutione musica of Boethius, created the false impression that the Byzantine octoechos was inherited directly from ancient Greece.^[4]


Originally used to designate one of the traditional harmoniai of Greek theory (a term with various meanings, including the sense of an octave consisting of eight tones), the name was appropriated (along with six others) by the 2nd-century theorist Ptolemy to designate his seven tonoi, or transposition keys. Four centuries later, Boethius interpreted Ptolemy in Latin, still with the meaning of transposition keys, not scales. When chant theory was first being formulated in the 9th century, these seven names plus an eighth, Hypermixolydian (later changed to Hypomixolydian), were again re-appropriated in the anonymous treatise Alia Musica. A commentary on that treatise, called the Nova expositio, first gave it a new sense as one of a set of eight diatonic species of the octave, or scales.


In medieval theory, the authentic Dorian mode could include the note B♭ "by licence", in addition to B♮.^[5] The same scalar pattern, but starting a fourth or fifth below the mode final D, and extending a fifth above (or a sixth, terminating on B♭), was numbered as mode 2 in the medieval system. This was the plagal mode corresponding to the authentic Dorian, and was called the Hypodorian mode.^[6] In the untransposed form on D, in both the authentic and plagal forms the note C is often raised to C♯ to form a leading tone, and the variable sixth step is in general B♮ in ascending lines and B♭ in descent.^[7]