On 3 April 1827 a service was held in Vienna’s Augustinerkirche to commemorate the death of Beethoven eight days earlier. This occasion, which included a performance of Mozart’s Requiem, presented an opportunity for the Viennese musician Ignaz von Seyfried (1776–1841) to provide a specially written ‘Libera me’, which was one of the Requiem Mass texts that Mozart did not set. Seyfried’s offering was perfectly suited to Mozart’s unfinished work: it is in the same key of D minor, is scored for similar SATB forces, and matches Mozart’s distinctive orchestral sonority. This ‘Libera me’ setting was widely used in nineteenth-century Vienna, both in its original version for voices and instruments, and for voices and organ alone. The present edition allows for both types of performance.