Let's face it, Robert "Cabinet of Dr Caligari" Wiene's 1926 film loosely based on Strauss and Hofmannsthal's 1911 "comedy for music" is a mostly inartistic ramble. Historically, though, it proves fascinating.

How do you make a venerable warhorse frisk like a coltish show-pony? Hire William Christie as the trainer.

William Christie chose a suitably light and breezy programme for this warm summer evening’s concert at St. John’s Smith Square. The concert was titled “Bach goes to Paris”, with works chosen to highlight the connections between the German master and his French contemporaries. But, more significantly, they showcased Christie’s deep affinity with French Baroque music, and the vibrancy and passion he brings to this repertoire.

Tradition – a choral spectacular for the penultimate night of the Proms – but with a twist – a youth choir and period instruments. Marin Alsop this evening led a spectacular Verdi Requiem, not least for the sheer scale of the chorus, the BBC Proms Youth Choir some 200 strong. The Orchestra of the Age of Enlightenment provided chacterful accompaniment, though sometimes struggled to compete, and the four soloists all delivered, particularly Tamara Wilson, here confirming her reputation as one of today’s leading Verdi sopranos.

Between the Berlin Philharmonic, Leipzig Gewandhaus Orchestra and Simón Bolivar Symphony Orchestra it has been a big week at the Proms, in every sense. Scope and scale have been the watchwords for the orchestral tectonics that have taken place, the sonic landscapes that have been formed and reformed. But concert-goers on Sunday night were hit with an operatic aftershock of overwhelming force, bringing this penultimate Proms week to a close next weekend’s patriotic spectacular will struggle to match.

It is interesting to note how, in the space of a few short decades, so-called “period instrument” performances of classical music have moved from edgy experimentation to the mainstream of the tradition. In last night’s Prom, the Orchestra of the Age of Enlightenment (OAE), born in 1986, was paired with the choir of King’s College Cambridge, tracing its origins back to 1441, to largely happy effect.

The Orchestra of the Age of Enlightenment is 30 years old, and last night it celebrated in style. The orchestra has a long association with the music of Weber, who became iconic of their pioneering work in presenting 19th-century repertoire on period instruments. His greatest work received an impressive performance last night, one that demonstrated the many virtues of their unique approach to the work of the Romantics. But it wasn’t all a success, and was let down by a surprisingly modest staging concept from the usually ambitious David Pountney.

When I was first commissioned by the Orchestra of the Age of Enlightenment I never dreamed that it would turn into a marriage of such long duration. The length and breadth of the collaboration has lasted over 20 years now, and long may it continue. It has afforded me the opportunity to get to know many of the players, which as time passes allows for an intimacy and trust that's very rare in photography, a profession which, like the proverbial shark, requires constant forward movement.

It’s always fun to watch the Orchestra of the Age of Enlightenment. As members of a self-governing orchestra, and often soloists in their own right, the players like to do things their way. Come the ripe second theme of the Bruckner Adagio and the cellos were giving it lashings of vibrato; muesli-wearing adherents to pure tone be damned. So were six of the eight basses ranged across the back of the Royal Festival Hall stage. That just left two basses, left-hand fingers resolutely unmoved.

A concert of Brahms chamber music I could understand, especially given a balance between early and late. An evening of orchestral Brahms, with or without voices, needs much more special pleading. It didn’t get nearly enough last night. An expanded Orchestra of the Age of Enlightenment, including nine very vigorous double basses – where did the extra players come from?