THREE weeks tomorrow, on Sunday October 2, there will be a seismic musical jolt as two major events collide on exactly the same day at precisely the same time. They will not be in the same place, with one occurring in Glasgow’s City Hall, while the other takes place in Edinburgh’s Usher Hall. Each of the events is a one-off that day, so you cannot go to both. Edinburgh will host a major concert by Stephane Deneve with his Brussels Philharmonic Orchestra, a team that has not been to Scotland, while in Glasgow the BBC SSO, in the City Hall with its new chief conductor Thomas Dausgaard, will stage a rather longer event. Both concerts begin at 3pm. And there the parallels just about cease, though not quite, as I’ll mention later.

Let’s focus on Glasgow. One of the most famous nights in the history of Western classical music occurred on December 22, 1808. Beethoven, having worked hard at it, got his hands on Vienna’s relatively new and much in-demand concert hall, the Theater an der Wien. The hall had a fine reputation and an already-renowned acoustic. Beethoven had heard some of his own music there. Now he wanted it for a special occasion. He had a bucket-load of new pieces he wanted to unveil to the world, a massive self-promotion in other words, and the Theater an der Wien was where he wanted to set out his stall with the brand new works. He couldn’t get the place easily, and had to compromise and take the date available, which was December 22 1808, in the dead of winter, with Vienna apparently freezing. On top of that, Beethoven was still writing music he wanted included in the programme. “The ink on some of the music was still wet,” was a contemporary comment. To compound the issue, the composer kept coming up with more ideas. He would give one of his famous improvisations at the piano; he had a reputation as a phenomenal improviser. And he decided to draw together the vocal and instrumental forces of the occasion by writing yet another new piece as a grand finale to feature all the musicians. So off it went, with Beethoven conducting, and the whole thing apparently under-rehearsed.

There was music galore in the programme, with a concert aria, the completed sections of a Mass, and, at the end, the daft-ish but fun finale of the Choral Fantasy. But there was also a core to the programme, and what a core. That 1808 concert witnessed the unveiling of three gigantic symphonic masterpieces with the world premieres of the Fifth Symphony and the Sixth Symphony, the Pastoral, along with the sublime Fourth Piano Concerto, with Beethoven as soloist.

To judge from contemporary reports, it was pretty uneven, though Beethoven was praised in the concerto. It fell apart in the grand finale with Beethoven losing the rag and shouting at them all to start again. The whole thing ran at some four hours.

Three weeks tomorrow, Thomas Dausgaard and the BBC SSO, with name soloists and RCS choral forces, are going to run the whole 1808 concert again in the City Hall. They’ll do it in three parts with several intervals. Why do it? I don’t honestly know. If championship was required for any of the symphonic music, then that would be reason, but the Fifth and Sixth Symphonies, and the Fourth Piano Concerto, are all ubiquitous and omnipresent in the classical repertoire. They are in the very DNA of concert programming and among the best-known and most-loved pieces ever written. They are also among the most played. Indeed, in the Usher Hall on that same afternoon, Stephane Deneve and his Brussels Philharmonic, before the roof-raising thunder and glamour of Respighi’s Pines of Rome, will open their own concert with – guess what? – Beethoven’s Sixth Symphony, the Pastoral. Did I say ubiquitous? The long Glasgow concert won’t be remotely authentic, with a gleaming, deluxe modern symphony orchestra in a warm, comfortable, centrally-heated, well-lit hall. I’ve known and lived the history of that 1808 concert for most of my life: for almost 60 years, I calculated the other night. I think about it a lot. I’ve written about it numerous times in the last 30 years. My dad once caught me, as a lad, pretending to be Otto Klemperer and "conducting" a recording of the Pastoral Symphony in front of a mirror. I still blush at the thought. I’ve stood in numbed silence in the Theater an der Wien, conjuring my own image of that 1808 concert, and of Beethoven’s presence. I don’t know what the SSO modern marathon, with all the other bits around the three masterpieces, aims to reveal. Breadth? Context? To be honest, I don’t really get the point.