The royal coffers had been drained by war, expenditure on ceremonial was cut, and artists whose lives had once been dedicated to the amusement of princes found themselves forced into commerce - including one Henry Purcell, who in 1690 re- directed his career away from the court and into the theatre with a piece called Dioclesian, which had a rare performance this week at St John's Smith Square from Trevor Pinnock and the English Concert. Dioclesian isn't, strictly speaking, opera but a play with music as a decorative extra. All the functional roles are spoken, which leaves nothing for the singers except to comment, anonymously, on the action, or to people the elaborate masques and ballets that embellish it, as nymphs and shepherds.
It follows that the music in a piece like Dioclesian is effectively free-standing and detachable. And Trevor Pinnock detached it, dropping the dialogue to leave an oratorio-like concentration of arias and ensembles never meant to run together. With the plot gone, it felt gutted: like a meal without a main course. But then the main course in 17th-century semi-opera isn't all that appetising, as anyone who saw Roger Norrington's Fairy Queen, complete with dialogue, at the QEH last year will know.
The plot of Dioclesian is actually no great loss. What we had instead was a demonstration of a composer flexing his muscles with the resources of a Baroque orchestra: a complement of instruments that would have been standard in France, but not here. As Purcell's printed dedication ruefully points out: 'Being farther from the Sun (King) we are of later Growth than our neighbour Countries.' In other words, England drags its heels again.
But Purcell would be pleased to know that England is not dragging its heels in the revival of his music. Important projects are under way for the tercentenary of his death next year; Trevor Pinnock is very much a part of them (the Dioclesian is about to be recorded); and from Tuesday's performance it's clear that his English Concert is in good form. The trumpets were rough, but the string sound was exemplary: buoyant and full. And the soloists were well cast, with singing of wonderful refinement from Nancy Argenta, Ann Monoyios and above all, Paul Agnew, a tenor of light but distinctive colouring who seems to grow in vocal stature every time I hear him. With such artistry applied to such uplifting music, this Dioclesian was an affirmative experience of the kind a certain government minister might have been envisaging recently when he told Britain off for being negative. A pity he wasn't there to hear it. Or, otherwise, support it.
There was another positive experience to be had at St John's last weekend, as the choir of Clare College, Cambridge celebrated a 15-year relationship with its director of music, Timothy Brown. Clare is not one of the old-guard Oxbridge choirs but, like Richard Marlow's choir at Trinity, it has a serious recording profile and a growing reputation: for a sharper, brighter, snappier personality than King's or John's. Clare, after all, is where John Rutter used to run the music; and the choir excels in the sort of repertory that runs in a Rutteresque direction along the Walton-to-Matthias axis of up- tempo choral writing. But it does other things besides; and its St John's concert programmed large-scale Bach and Mozart as well as small-scale novelties like a New Year's carol by Christopher Brown: brother of Timothy and a composer who, inexplicably, doesn't get much of a hearing these days.
Franz Schmidt has the same problem; and I confess that, until the Young Musicians Symphony Orchestra played his 4th Symphony at the QEH on Wednesday, I had never heard it live. But believe me, this symphony is a masterwork: an anachronism (written 1933) of Brucknerian tragic reflectiveness, profoundly tonal, and with more flesh on its bones than perhaps it needs, but none the less a score of compelling emotional force that ought to be secure in 20th-century symphonic repertoire. The YMSO played it beautifully, if rather slowly, with a strong, confident 1st trumpet: an essential asset in this piece. I wish the Prokofiev 2nd Violin Concerto before the interval had been as good, as gutsy or as coherent; but it came with an exceptional 20-year-old soloist, Daniel Hope, who made an instant impression in the way he shaped and made meaning from the violin's potentially shapeless opening phrase. Prokofiev 2 is a hard piece to shine in: there's a lot of scruffy passage-work that falls short of virtuosity and just results in the fiddle losing tone and profile. But Daniel Hope seemed to me to have real lyrical gifts and an enviably fluent technique. Remember the name.
Finally, a salute to Xerxes - back again at the Coliseum in Nicholas Hytner's flagship staging. Its smart, cool, stylishly post-modern humour is still a joy to watch: the most successful modern, 'found' equivalent to 18th-century convention I've ever encountered. And although the incorporation of Handel into his own opera, as an object of tongue-in-cheek veneration, is a bit redundant nine years after the Handel anniversary for which this production was first made, Hytner's idea of the piece as a study of curious obsessions bursting the constraints of formal nicety holds good - and is in any case fair game in opera that presents so blank a page to the director. Yvonne Kenny could look more engaged in what she does, but sings with glistening charm; Christopher Robson is the perfect all-round actor / singer, glorious in his two laments; and Ivor Bolton is a bold, brilliant conductor. It's a great show.
'Xerxes', 071-836 3161, Wed & Fri.