Wolfgang Amadeus Mozart wrote the Requiem mass in D minor (K. 626) in 1791. It was Mozart's last composition and is also perhaps one of his most powerful and recognised works, not only for its music, but also its obscure composition history, as there has always been a debate surrounding the work as to how much of the music Mozart managed to complete before his death, and how much was later composed by his friend and pupil Franz Xaver Sussmayr. Despite this, however, (or perhaps because of it) it has certainly taken a prominent place among the canon of Mozart's most iconic works.