The term ‘serenade’ evidently meant diffrerent things to Mozart at different times. The Posthorn is a Salzburg work, composed in 1779, and presumably intended as an example of the Finalmusik that accompanied the ebb and flow of university terms. Eine kleine Nachtmusik, meanwhile, dates from 1787 and was composed in Vienna, where it served as a notturno. Two marches flank the Posthorn, with which they are probably associated as processional music, and Eine kleine is restored to its original five-movement form with the addition of a minuet from the much earlier String Quartet in G, K80.

None of this is demanding music: indeed, the Posthorn is full of Mozartian musical jokes, from the Allegro that bursts impatiently into the slow introduction to the almost wilful over-use of Salzburg clichés, as if the 23-year-old composer were sticking two fingers up at the archbishopric out in the sticks that he so longed to leave. Then there’s the posthorn itself, its five-note range exploited with deadpan virtuosity by Hannes Rux.

Eine kleine is something completely different: a fine example of the art that conceals art, with a formidable construction and harmonic ingenuity that belie its status as high-class light music. The Cologne Academy’s period instruments impart a welcome, grainier texture than some more sumptuously upholstered modern-instrument recordings. The interpolation of such an early minuet may seem anachronistic but Mozart apparently retained a fondness for the work for many years after its composition. (And anyway, you can always programme it out for the ‘classic’ four-movement work.) Undemanding, yes, but an hour and a quarter of pleasurable music in fine performances.