Mystique surrounds the genesis of Mozart’s Requiem: the mysterious commission; the deception of his widow, Constanze, so she could collect payment; the uncertainty of authorship – Mozart? Süssmayr? and which parts by whom? – and Mozart’s belief, as his health failed, that he was composing to mark his own death. Written in 1791, the work bows respectfully to the Baroque masters, Bach and Handel. However. the scoring of the work is unusual – no flutes, oboes or French horns – but basset horns (early clarinets) and trombones, the latter having a starring role in the Tuba Mirum.
The work opens with the Introitus: Requiem aeternam scored for bassoon and clarinet and clearly echoes Handel, whilst the soprano’s intervening Te decet hymnus is a traditional chorale. The Kyrie eleison is written in a contrapuntal style worthy of Bach, the fugal writing both grim and exciting as it builds to a gripping climax. The Dies Irae begins the six-movement Sequentia. Scurrying figures on the strings accompany the choir’s angry phrases, sung in block chords. The Tuba mirum opens with a bass soloist, accompanied by flowing lines on the trombone, each voice joining the bass as the movement progresses. The brief Rex tremendae packs a punch in only 22 bars, the choir and orchestra in counterpoint. The movement ends with a sigh on Salva me. It is followed by the aria Recordare, arguably the centrepiece of the work, the soloists’ melodies intertwining with great beauty, and the Confutatis.
Mozart’s death interrupted the completion of the Lachrymosa; after the opening eight bars, it was completed by Süssmayr, who also finished the two movements known as the Offertorium – Domine Jesu and Hostias. The Sanctus, Benedictus and Agnus dei are almost entirely the work of Süssmayr, but by ending the work with a return to the Introitus, this time to the words Cum sanctis tuis, Mozart’s fugal writing is heard again in all its glory.