In the early 1780s, Baron von Swieten of Vienna held soirées every Sunday. He had been ambassador to the Prussian Court in Berlin, where he became enamoured with the music of Handel and Bach. Among the musicians in attendance was Mozart, who contributed string arrangements of Bach manuscripts. 

Mozart worked from hand-written copies; Bach’s keyboard music was not published until the early 19th century. The fugues come from both books of the Well-Tempered Clavier, but new adagio introductions replace Bach’s original preludes, which were apparently unknown to the Viennese musicians. Scholars originally assumed the adagios were Mozart’s work, but it is now thought his arrangements were straightforward transcriptions of von Swieten’s manuscripts. He did however contribute music of his own in the style of Bach, notably an Allegro (unfinished) and Fugue in C Minor for two fortepianos. 

The Akademie für Alte Musik, who had a hit at this year’s Sydney Festival, have put together a disc. Most are played by strings, but one is heard in a wind arrangement. Four out of nine have no Köchel number, indicating doubt about whether Mozart arranged the others. They are played on period instruments by a skilful and sensitive band. If the sound of the two fortepianos in the C Minor Allegro conjures up a silent film accompaniment, that is entirely the fault of my corrupted ears!

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