the only modern diatonic mode in which the tonic triad is a diminished chord, which is considered dissonant. This is because the interval between the root and fifth of the chord is a diminished fifth. For example, the tonic triad of B Locrian is made from the notes B, D, F. The root is B and the fifth is F. The diminished-fifth interval between them is the cause for the chord's dissonance. The name "Locrian" is borrowed from music theory of ancient Greece. However, what is now called the Locrian mode was what the Greeks called the Diatonic Mixolydian tonos. The Greeks used the term "Locrian" as an alternative name for their "Hypodorian", or "Common" tonos, with a scale running from mese to nete hyperbolaion, which in its diatonic genus corresponds to the modern Aeolian mode. In his reform of modal theory in the Dodecachordon (1547), Heinrich Glarean named this division of the octave "Hyperaeolian" and printed some musical examples (a three-part polyphonic example specially commissioned from his friend Sixtus Dietrich, and the Christe from a mass by Pierre de La Rue), though he did not accept Hyperaeolian as one of his twelve modes. The usage of the term "Locrian" as equivalent to Glarean's Hyperaeolian or the ancient Greek (diatonic) Mixolydian, however, has no authority before the 19th century. Usage There are brief passages in works by Sergei Rachmaninov (Prelude in B minor, op. 32, no. 10), Paul Hindemith (Ludus Tonalis), and Jean Sibelius (Symphony No. 4 in A minor, op. 63) that have been, or may be, regarded as in the Locrian mode. Claude Debussy's Jeux has three extended passages in the Locrian mode. The theme of the second movement ("Turandot Scherzo") of Hindemith's Symphonic Metamorphosis of Themes by Carl Maria von Weber (1943) alternates sections in Mixolydian and Locrian modes, ending in Locrian. English folk musician John Kirkpatrick's song "Dust to Dust" was written in the Locrian mode, backed by his concertina. The Locrian mode is not at all traditional in English music, but was used by Kirkpatrick as a musical innovation. Björk's "Army of Me" is a rare example of a pop song whose verse is written in the Locrian mode. Various metal artists such as Metallica and Slayer have used the Locrian scale's diminished second and fifth intervals in chromatic riffs. In terms of true Locrian, rather than simply using Locrian scale degrees within octatonic or