Dies Irae is a sequence of music done during a Mass Of The Dead but may be done as seperate pieces. It is arranged using Soprano, Alto, Tenor and Baritone solo voices with support from Soprano (Mezzo Soprano), Alto (Contralto), Tenor (Countertenor), and Bass voices. Instrumentation is Flute, Oboe, Bb Clarinet, Bassoon, Bb Trumpet, French Horn, Trombone, Violin, Viola, Cello, Contrabass, Harp (or Piano, Timpani and various Percussion Instruments.)