Because of the importance of the major scale in modern music, the Lydian mode is often described as the scale that begins on the fourth scale degree of the major scale, or alternatively, as the major scale with the fourth scale degree raised half a step. This sequence of pitches roughly describes the scale underlying the fifth of the eightGregorian modes, known as Mode V or the authentic mode on F, theoretically using B but in practice more commonly featuring B.
The name Lydian refers to the ancient kingdom of Lydia in Anatolia. In Greek music theory, there was a Lydian scale or "octave species" extending from parhypate hypaton to trite diezeugmenon, equivalent in the diatonic genus to the medieval and modern Ionian mode .
In the chromatic and enharmonic genera, the Lydian scale was equivalent to C D E F G A B C, and C C E F F A B C, respectively, where signifies raising the pitch by approximately a quarter tone.
Medieval Lydian mode
In the Middle Ages and Renaissance, this mode was described in two ways. The first way is the diatonic octave species from F up to F an octave above, divided at C to produce two segments:
The second is as a mode with a final on F and an ambitus extending to F an octave higher and in which the note C was regarded as having an important melodic function. Many theorists of the period observed that B is used more typically than B in compositions in Lydian mode.
Modern Lydian mode
The Lydian scale can be described as a major scale with the fourth scale degree raised a semitone, making it an augmented fourth above the tonic, e.g., an F-major scale with a B rather than B. This mode's augmented fourth and the Locrian mode's diminished fifth are the only modes to have a tritone above the tonic.
The 12th-century "Hymn to St. Magnus" from the Orkney Islands, referencing Magnus Erlendsson, Earl of Orkney, is in Gregorian mode or church mode V, extending from the E below to the octave above, with B's throughout, in two-part harmony of mostly parallel thirds. The Sanctus, Agnus Dei, and Ite, missa est of Guillaume de Machaut's Messe de Nostre Dame feature extensive use of F and B, as well as F and B.
Romantic
A rare, extended use of the Lydian mode in the Classical repertoire is Simon Sechter's 1822 Messe in der lydischen Tonart . A more famous example from around the same time is the third movement of Ludwig van Beethoven'sString Quartet No. 15 in A minor, Op. 132, titled by the composer "Heiliger Dankgesang eines Genesenen an die Gottheit, in der lydischen Tonart". The alternating passages in F use the Lydian scale with sharp fourth scale degree exclusively. Charles-Valentin Alkan's Allegro barbaro is written strictly in F Lydian, with no B's present at all. Anton Bruckner employed the sharpened fourth of the Lydian scale in his motet Os justi more strictly than Renaissance composers ever did when writing in this mode.
Modern
In the 20th century, composers began once again to exploit modal scales with some frequency. George Enescu, for example, includes Lydian-mode passages in the second and third movements of his 1906 Decet for Winds, Op. 14. An example from the middle of the century is the scherzo movement of Carlos Chávez's Symphony No. 3. The movement opens with a fugue subject, featuring extremely wide leaps, in C Lydian with following entries in F and G Lydian.
Jazz
In Lydian Chromatic Concept of Tonal Organization, George Russell developed a theory that became highly influential in the jazz world, inspiring the works of people such as Miles Davis, John Coltrane, Ornette Coleman, and Woody Shaw
