The quite rarely performed K337 was Mozart's last complete setting of the Mass; it was written in Salzburg in the spring of 1780, a year after the better known Coronation Mass, K317. The Coronation was intended for the Easter Sunday service in Salzburg Cathedral in 1779, K337 for the same event the following year. Although it is described as a missa solemnis, and has the elaborate orchestral writing appropriate to that type, it is in fact a very brief setting, as the reformed Salzburg liturgical procedures under Archbishop Colloredo required. At any rate, Mozart considerably modified his usual Mass style. As in the Coronation, the customary big formal fugues to end the Gloria and the Credo are lacking, though instead the Benedictus, which in the past he had usually set as a gentle solo piece, is treated in a rather austere though quite brief fugue. It is in some ways a more original work than the Coronation, though not actually quite as appealing. There is a very subdued though quietly heartfelt Kyrie, then a very brilliant and vigorous Gloria—well, it's specially vigorous under Nikolaus Harnoncourt, who makes the most of it, if not indeed a bit more than that, with his very pointed accents and his vivid realization of the orchestral writing (listen to the fierce trombones). He certainly secures fine, alert choral singing, and lively violin playing too. In the Credo, a single movement with a slow interlude (a soprano solo) at ''Et incarnatus'', he tends to conduct rather heavily, with clumping rhythms, but the choral singing is again first-rate. In the Sanctus there is a delightfully cheerful, almost witty ''Hosanna''; and the expressive climax comes in the Agnus, a soprano solo, on a theme hinting at ''Porgi amor'' (curious that ''Dove sono'' comes at the equivalent point in K317), with obbligato writing for oboe, bassoon and solo organ to an accompaniment for muted upper and pizzicato lower strings. As sung here by Barbara Bonney, the effect is ravishing.
The other works are slighter, and indeed the Regina coeli has always seemed to me a fairly routine piece (though the violin chirpings are somewhat out of the ordinary). The first of the two sacramental litany settings, K125, also has some unexceptional numbers—it is nothing like as fine as the later setting, K243—but there are attractive arias for the soprano, again the admirable Bonney, and the tenor, Uwe Heilmann, who is also quite eloquent. Harnoncourt makes much of the sombre, dramatic slow choral numbers; there is a big fugue for the ''Pignus'' (the effect is rather plodding here, I think Mozart's fault as much as Harnoncourt's) and for the Agnus an expressive aria, for soprano once more, leading to the closing chorus. The other soloists are no more than competent, and Gilles Cachemaille's French style slightly obtrudes in his solos. Some listeners may feel that the element of giving a 'performance', colouring and shaping the music, is a bit overdone, particularly for liturgical works, but on the whole I think that Harnoncourt's capacity to put the music across with vitality amply justifies itself.'