For too long the Gregorian chant has been accompanied from the perspective of the 19th century in the harmonic-diatonic sense. It is therefore to be welcomed to edit a modern accompaniment of the chorale requiem that corresponds to the feeling of our time and does justice to the oriental-antique character of the melodies.'.
(Olivier Messiaen in an interview with Benno Ammann in Darmstadt-Kranichstein 8 Sept. 1961.)
