It would be conventional, almost instinctive, to say that Saturday’s orchestral job could not have been more different than Friday’s. Actually it could, not least in point of scale.

Granted, we were performing Mendelssohn’s Elijah, one of the ‘warhorses’ (the term of a chorus member speaking to me, not my own!) of the choral society repertoire. It requires organ, Romantic symphony orchestra, a large choir, a female semichorus and five vocal soloists; and it is lengthy. Even with two numbers and part of a third cut, the music alone must have taken up over two hours (plus interval etc. in terms of looking at how long the concert lasted).

However, Mendelssohn’s symphony orchestra is quite restrained, compared to Wagner’s or Mahler’s. And in fact, we weren’t using Mendelssohn’s orchestra. Constraints – which, depending on who you were talking to, might have been financial (the orchestra were all being paid quite ‘properly’ professional fees), spatial (it was certainly very cramped with the choir and orchestra in the crossways of a large church with non-negotiable Victorian pews, leading to some drastic compromises on positioning) or musical (the choir were numerous, at 50 or 60 in my guess, but not a particularly youthful or forceful bunch) – led to the use of a reduced orchestration, the wind parts rearranged to roughly halve the number of players and correspondingly it being possible to balance them with a small body of strings. The most extreme example of this was that there were only two cellos; but there is an aria late on in the work with a (gorgeous) solo cello countermelody, plus a bass-line in the remaining cellos. Or, as on this occasion, the remaining cello.

The result was perhaps to slightly reduce the hammer-blow effect of Mendelssohn’s biggest moments (he definitely aimed for the most fire and brimstone version of an Old Testament miracle-working prophet he could get); less because they were less absolutely loud, more because a smaller group has less dynamic range to play with and so the gap between quietest and loudest is less shockingly huge. But it certainly remains a work to make a powerful first impression – or even, on me, second, since I played it (in the original, and feeling correspondingly more adrift in a sea of musicians with a conductor somewhere on the far horizon) a couple of years back.

It is also an odd composition, something which familiarity of the choral society circuit perhaps blurs. Romantic composers did not generally try their hand at oratorio – most of the similar works in existence are from the late Baroque, Handel in particularly churning out a rapid succession in his London years. Haydn’s Creation, nearly half a century later, is partly a deliberate effort to reinvent the oratorio for the Classical era and partly a backward-looking attempt to ape an older style; and it is more or less the last oratorio to have remained in the repertoire until Elijah. As such, the genre works a little like an unstaged version of Baroque opera, with a fairly dependable alternation of recitative (carrying forward the plot) and aria or soloist group singing (conveying emotional responses to the last section of recitative). Oratorio, perhaps because of its sacred nature (the plots are almost exclusively biblical) possesses rather more in the way of choruses, either part of the dramatic action or reflecting upon it; which are frequently polyphonic, imitative or even fugal, as grand set-piece movements often are in Baroque works of all kinds, and continued to be in church music for rather longer.

And that brings me, in a roundabout fashion, to the main odd thing about Elijah. The lyrical content – particularly the arias – is written in Mendelssohn’s early Romantic style, and some of it is gorgeously expressive (though I admit, to my surprise, after playing them on consecutive days, it was Bach’s tunes, not Mendelssohn’s, that stuck in my head. In fairness Bach’s violin parts, even accompanying ones, contain many more melodies than Mendelssohn’s viola parts; such is the nature of their respective compositional approaches). The recitatives perhaps occasionally smack of older styles, but less had changed about the way recitatives were written, except for their accompaniment. In that, Mendelssohn is thoroughly of his time, demanding that the conductor cue the entire string section, and occasionally some winds too or (much more rarely) in their place, in interjecting stabs and sustained chords around the essentially free speech rhythm of the vocal line. This both demands a much greater degree of group concentration (even in Haydn and Mozart, recitatives are accompanied by continuo only, usually making them a three-handed effort between singer, harpsichord or fortepiano player and principal cellist) and makes for very hard work for the strings, who get hardly any time off from playing in the entire piece!

The choruses, however, are decidedly schizophrenic. Rather like post-Baroque composers writing large-scale Mass settings, Mendelssohn feels obliged to at least gesture towards fugue, and often attempt it full-scale. He does so frequently – in almost every big chorus in fact. This constitutes a real departure from his usual compositional environment, and it is very easy to hear and indeed see the shift from one of the inner parts. Compared to the generally monumental and textured approach of most Romantic orchestration, it is a sudden shift of gear, and with the best will in the world I’m still not quite sure he pulls it off. There is usually great energy to the result, as there almost always is to imitative textures, but also a slight sense of obligation and constraint – a sense that, as an alternative and (for his musical culture) so to speak secondary mode of expression, it had not been practised enough to become a means to what it was meant to express, and instead became an end in itself.

Densely polyphonic writing, and fugue in particular, had a peculiar history from the mid-eighteenth to the mid-nineteenth century. It continued to be de rigueur for larger sacred works (of which almost all leading composers wrote some), and writing fugues for keyboard instrument continued to be a regular part of advanced musical training – Bach being taken as the model for this, and that composer being known for quite some time almost solely as a creator of polyphonic keyboard music (which was more studied than perhaps listened to with enjoyment). It forms part of a toolkit of ‘untimely rhetoric’ (read: old-fashioned musical technique) which critics have identified as characteristic of early Classical ‘severe’ minor-key writing – this essentially a delayed part of the fading away of Baroque compositional approaches then. Thereafter, there is a marked tendency for it to be explored by major composers in isolation over against prevailing taste; Mozart famously employed fugal entries (though they are not thoroughly ‘worked through’) in the last movement of his last symphony, at a point when he was losing popularity and in works whose purpose is disputed; Beethoven ‘discovered’ both Bach and Handel late in his career and concluded his last string quartet, one of a truly enigmatic and difficult set of works, with a monumental fugue which his publisher forced him to replace with a more conventional conclusion.

Mendelssohn himself is involved in the real shift in popular taste here. He came across some of the non-keyboard works and carried out a quite extraordinary championing of them in the concert hall, bringing concerti, orchestral suites and so on back into performance and insisting on their high musical value. This led in turn to wider interest and investigation, and from Mendelssohn’s efforts we can trace, for instance, Brahms’s almost obsessive study of the Bach cantatas, the rediscovery of such lost masterpieces as the solo violin works, and ultimately the composer’s elevated place in the canon.

In order to realise the importance of this, it is necessarily to think back to a much more faddish classical concert world than today’s. Many composers barely kept the concert stage after their own death; indeed, those who lived long and innovated little might well find themselves rejected as dated well within their own lifetimes. Many (though far from all) adherents of a particular style or era tended to despise its predecessors: Hummel, who was taught by Mozart, found his music attacked as pretty (in the worst sense of the word) and insubstantial, partly on the grounds of that same tutelage, despite the high regard he was held in by Beethoven (who represented, in general opinion anyway, the Romantic new broom that had swept away the Classical lack of true feeling). Today’s chronologically cosmopolitan concert hall, let alone record collection, is a relatively recent innovation in aesthetic appreciation.

To proclaim the virtues of century-old music in the mid-nineteenth, then, was a bold step for Mendelssohn, even if some pendulums had swung one way and most of the way back in the meantime. And perhaps it is not surprising that he should try to imitate some aspects of the music he had discovered with wonder, as others were to perhaps more comprehensively integrate elements of it. What is more surprising is maybe not that Mendelssohn trying to do Handel is occasionally clunky, but rather that the result is as successful as it is, even today when more time separates its performers and hearers from its composition than separated Mendelssohn from Handel.