Mozart’s Requiem is the earliest such work to have broken free from its liturgical bonds and become a regular fixture in the concert hall and on record. Even in its unfinished state, it represents the peak of Mozart’s mature style, balancing perfectly the dramatic and the devotional, the antique and the modern.

Mozart had been involved with church music from childhood in Salzburg, the earliest of his Masses – the Waisenhausmesse, K139, a large-scale, cantata-style work – being composed when he was a boy of 12. His break with Salzburg led to a decade with only sporadic ventures into sacred music, the most breathtaking being the Mass in C minor, in which we hear his first foray into the styles of Handel and Bach that would inform so much of the music of his Vienna decade. By the time he came to write the Requiem, he leant on models including The ways of Zion do Mourn – part of Handel’s Funeral Anthem for Queen Caroline, which is a clear forerunner of the Requiem’s Introit – and Michael Haydn’s Requiem for Archbishop Schrattenbach, in which he and his father had played in Salzburg in 1771: Mozart unmistakably based his ‘Domine Jesu Christe’ on the younger Haydn’s. Mozart arranged Messiah for performance in 1789 and manifestly learnt much from Handel’s style.

Mozart’s other music of mourning includes the wonderful, dark-hued Masonic Funeral Music, with its contrabassoon and trio of basset-horns. In 1791 church music was once again on his mind and the richly scored Kyrie in D minor, K341, has become associated with this renewed interest.

After the Requiem, Mozart’s posthumous collaborators also essayed the form. The Requiem by Franz Xaver Süssmayr – author of (most of) the ‘standard completion’ of the Mozart, offered a far less dramatic take on the text, while Joseph Leopold Eybler’s choral music shows the palpable influence of his erstwhile mentor. And in 1792, having heard of his young friend’s death, Haydn encoded his own memorial to Mozart in his Symphony No 98’s slow movement.