Classical music voice teachers or from completion of a formal program offered by a Conservatory, college or university, such as a Bachelor of Music or Master of Music degree (which includes individual lessons from professors). In classical music, "...extensive formal music education and training, often to postgraduate [Master's degree] level" is required. Performance of classical music repertoire requires a proficiency in sight-reading and ensemble playing, harmonic principles, strong ear training (to correct and adjust pitches by ear), knowledge of performance practice (e.g., Baroque ornamentation), and a familiarity with the style/musical idiom expected for a given composer or musical work (e.g., a Brahms
Music for the Requiem Mass aeternam" (two different settings), and "I heard a voice from heaven." Some composers have written purely instrumental works bearing the title of "requiem", as famously exemplified by Britten's "Sinfonia da Requiem". Hans Werner Henze's "Das Floß der Medusa", written in 1968 as a requiem for Che Guevara, is properly speaking an oratorio; Henze's Requiem is instrumental but retains the traditional Latin titles for the movements. Igor Stravinsky's "Requiem canticles" mixes instrumental movements with segments of the "Introit," "Dies irae," "Pie Jesu," and "Libera me." American composer Dan Forrest has written "Requiem for the Living", a five-movement piece that follows the