The 1970s were years of retrenchment and stock-taking after the great era of post-war experiment. Boulez, Cage and Stockhausen had made their points; the cauldron of the avant-garde was simmering on a lower gas. Apart from the last works of Britten and Shostakovich, the landmarks of the decade were laid principally by Carter, Henze and Ligeti, while further out came signs of an advancing comfort zone. The minimalist roadshow was about to start.
Rattle's journey into all this started last week, with a CBSO concert featuring three generations of British composers who could be said to have set the standards of the Seventies on their own home ground. The grand old man then, as for so long after, was Michael Tippett, whose 4th Symphony (1977) was the big work in the programme, playing in memoriam. Harrison Birtwistle represented the mid-generation, with his ruggedly impassive Triumph of Time (1972), untouched and unmellowed by the passing years. And for the youngsters there was the 3rd Symphony of Oliver Knussen: written slowly and (like many Knussen scores) traumatically between 1974 and 1979, its single-movement form hard-won but worth the fight.
The would-be minimalists crept into another Millennium concert this week, given by the London Sinfonietta at the South Bank under Markus Stenz. The theme was music as an act of faith, and the star (inevitably) John Tavener who, at the time of writing his Requiem for Father Malachy (1973), hadn't settled into the rediscovery of Byzantium that makes his current work so suitably funereal. But in its spiky, spare, Stravinskyan way, the Requiem points to what would come; and Tavener's latter-day description of the piece as "like sniffing around a restaurant without actually going in" is musically as well as spiritually accurate.
For contrasting statements of Seventies faith, the Sinfonietta also programmed Mortuous Plango, Vivos Voco, Jonathan Harvey's electronic classic, and Morton Feldman's Rothko Chapel. Harvey's sonorous collage of chiming bells and boy sopranos sounds like soft stuff now, positively Merchant-Ivory. But it's effective, colourful and brief: a quality that Feldman's music rarely values. Rothko Chapel celebrates the contemplative shrine in the museum district of Houston, Texas where a series of large black Mark Rothko canvases cover the walls. Having seen the chapel, I can vouch that it's a place where time has no dominion. You surrender to the Rothko black and watch as, gradually, the surface variations in the blackness sharpen into patterns. Feldman's score works similarly, and rewards your patience with a fragile, childlike melody for solo viola that emerges finally and delicately from the long, long void.
One thing they didn't have in the 1970s was Handel opera: not, at least, in the quantity we get today. Last weekend there were two running side by side in Antwerp, both with a conspicuous British input and one - Semele at the Flanders Opera - with an ENO-type cast, including Rosemary Joshua, Charles Workman, Della Jones and Sara Fulgoni. Staged by Robert Carsen with designs by Patrick Kinmonth, it rehouses Handel's Roman gods in something that looks suspiciously like Buckingham Palace. And if I add that Della Jones's Juno appears robed in state with orb, sceptre and handbag - from which she then produces a pair of reading glasses - you might think the worst. But on the contrary, it's ultra-stylish, lyrical, controlled. The comedy is restricted to the Juno scenes, leaving Semele herself to be a pretty serious character. And far from the usual preening wannabe, this Semele is truly touching and vulnerable: a small-time girl sucked into big-time games that overwhelm her. Her relationship with Jupiter is real and erotic. Her death - collapsing in a nightdress at the foot of Juno's throne - is compelling. The Diana parallel is somehow not distasteful, though there's talk of making changes when the show plays London next year.
Rosemary Joshua is loveliness incarnate in the title role; Jones's crown-and-spectacles routine is gloriously funny; and though Mark Minkowski conducts with the manic vigour of baroque statuary in motion, everything is shaped, intelligent, and buoyantly alive. This show is a pure delight and definitely worth the trip.
Tolomeo, staged by the Antwerp-based touring company Muziektheatre Transparant, isn't quite so stunning. But then Transparant hasn't the resources of the Flanders Opera, and Tolomeo isn't such a great piece. It counts among the also-rans in Handel's stable, and seems to have given Lindy Hume, the Australian director, a hard time. Perversely, she stages a pastoral, largely outdoor opera in enclosed sets; so Tolomeo's bedroom, where we seem to be throughout Act I, becomes an oddly public thoroughfare, with people bursting in on all sides. But there's striking imagery. The lighting is effective. And the singing is fine when you can hear it from voices which, though perfectly formed, are small. Anne Cambier's Seleuce is enchanting and so, in the title role, is Jonathan Peter Kenny, who has one of the most affecting countertenor voices around. But in both cases, you lose a lot when the singers are anywhere but at the front of the stage. And that's a shame because, with artists of this calibre, you want to savour them.
Back in London, there wasn't much to savour in Ambroise Thomas's Mignon, which played this week at the Bloomsbury Theatre. A decorative mid-19th- century confection, typical of French opera comique before Carmen raised the stakes of the genre, it's a piece that needs reserves of charm and melody, which are in short supply here. Netia Davan-Whetton's staging falls over itself to look sharp and streetwise on a shoestring budget, only to look empty and pretentious. The voices are poor, with a miscast Mignon in Klara Uleman, who plays the gamine like a male falsettist. And the most I can say for the show is that it's another brave but wasted effort by University College Opera to unearth neglected repertory.