Fourteen years ago, Frankfurt's was just an ordinary provincial ballet company offering ordinary ballet fare. Then a lanky, earnest, fast-talking American, William Forsythe, was given the job as director, with carte blanche to do what he liked with the repertoire. Out went old ballets - the recent old, as well as the Nutcrackers and Giselles - and in came an avant- garde body of work made by one man and one man only: William Forsythe. The good bankers of Frankfurt threw money at the project. The young of Frankfurt clamoured for tickets. Suddenly it was cool to go to the ballet. The company went heavily into profit. Could such a thing ever happen here?
To judge by the audience response to the company's very first visit to Britain, the enthusiasm is there. And the programme Ballett Frankfurt presented at Sadler's Wells last week was hardly an easy-reader introduction to Forsythe's "post-structuralist" style. Some punters may have thought they knew what they were in for. The Royal Ballet has three popular Forsythe works in its repertoire, but for all their angularity and 190-degree kicks, those works remain unmistakably grounded in the classical style. The stuff Forsythe makes for his own company is a different kettle of bratwurst altogether.
Following what he calls "an aesthetic of perfect disorder", Forsythe puts a bomb under the traditional etiquette of stage performance, creating a brave new world from the rubble. His dancers don't give a fig for charming the audience. Utterly absorbed in their twitching, jelly-limbed, knot-tying selves, they don't cast so much as a glance into the auditorium, let alone a smile. When they've finished a sequence of movement they stand around idly, hands on hips, or simply saunter off. The audience is thus cast in the role of fly on the wall, the performance becomes a private activity.
Nor has Forsythe any truck with traditional habits of staging. At Sadler's Wells, he whipped out the ceiling, the back wall and the wings to make one huge barn-like performing area, with the result that for an instant, when the curtain rose, you saw the dancers as tiny miniaturised figures, marooned in an ocean of space.
The opening piece, Hypothetical Stream 2, plays on this mood of isolation, with a mournful, repetitive score that suggests the opening bars of Das Rheingold played on trombones and ships' foghorns. Dancers form into knotty clusters (apparently inspired by paintings by Tiepolo); duets express a tenderness that constantly tilts into violence; individuals pit themselves against the emptiness around them with a kind of fervid desperation.
Lots of things happen at once, so the eye is drawn hither and thither until, suddenly, a moment of casual grace is caught and frozen in the melee, or someone performs a stunt of such unbelievable deftness (like a jump-spin that starts, and lands, cross-legged) that you want to stop the tape and play it back.
But this is old-fashioned obscurantist modern - not the kind of modern that sets the joint jumping. It was the next piece, Enemy in the Figure, that showed Forsythe able to create the kind of immediate, visceral excitement that makes you forget to worry about what it all means.
In a big black space divided by a wavy wooden screen, a man scoots around with a huge spotlight on wheels, swooping on figures in the darkness like a manic TV cameraman. A figure sprints left to right trailing a length of hosepipe, which is then made to wiggle and jump like the VDU on a heart monitor. A dancer in crazy fuzzy trousers performs a leaping voodoo dance against a wall; travelling bodies pirouette at such speed the only way they can stop is to crash. Yet amid these scenes of organised chaos, a pair of girls in white can perform a glimmering, delicate sequence, for all the world as if they were dancing to Chopin.
It's this consummate control of mood and counterpoint that marks out Forsythe's ballets as more than just a vehicle for modish athletics. In Quintett, he even shows himself able to deliver pure, lyrical emotion (and when was the last time modern dance gave you any of that?). To the Gavin Bryars score Jesus's Blood Never Failed Me Yet - a looped tape of an old tramp croaking out his version of the hymn - five dancers explore what it is for the body, and perhaps even the spirit, to fail. In a constant state of imminent collapse, they wobble and crumple, legs buckle, torsos cave in.
Yet now and again, as in life, a rapturous arabesque breaks through and is held for a ravishing couple of beats before subsiding. The knowledge that Forsythe made this piece for his ill young wife just before she died gives an added poignancy.