Terezin: the name inspires both horror and wonder. This Czech garrison town, also known as Theresienstadt, was home to one of the most extraordinary cultural phenomena of the Second World War. The inmates of its Jewish ghetto included swathes of the intelligentsia of Prague and Brno who were deported there. Confined within its walls, desperately overcrowded, disease-ridden and malnourished, a generation of composers, writers, artists, musicians and actors turned to their art to keep their spirits alive. The composers, in particular, created some of their finest work in Terezin before being murdered by the Nazis.
Out of some 150,000 Jews in Terezin, around 88,000 were sent to Auschwitz-Birkenau and other death camps; 33,000 died in the ghetto; only 17,247 people emerged alive. When the Nash Ensemble opens its Terezin Weekend at the Wigmore Hall later this month, it will be a chance - still too rare - to hear music written by that lost generation.
The weekend was devised by the Nash Ensemble's artistic director, Amelia Freedman, for whom it has been a labour of love. She has assembled a schedule involving concerts, talks by three survivors, an exhibition of children's drawings documenting life in Terezin, and film screenings including a powerful documentary by director Simon Broughton.
To Freedman, the music offers the strongest message of all. "It is vital that this music should be heard," she says. "These Czech composers included Hans Krása, Gideon Klein, Pavel Haas and Viktor Ullmann, plus Erwin Schulhoff, who wasn't in Terezin but died in the Wülzburg concentration camp. They should have been the successors to Janácek. Instead, they were wiped out. Their music is top quality and it should now become part of the mainstream repertoire. More than anything, their work proves the strength in adversity of the human spirit."
But since the music is so superb - and it really is - why did it take so long to achieve recognition? Wolfgang Holzmair, the Austrian baritone who takes centre stage in the concerts, has made its rehabilitation a personal mission and holds strong views on why it languished in obscurity until as recently as the 1980s. "After the war, even when the music was known it was not played," he says. "I think it was a political statement. It was not politically opportune to play this music. There were many people in the higher echelons of concert promoters and record companies who simply did not want it to be heard."
Does he mean ex-Nazis? "Not ex-Nazis as such, but people who were influenced by that political system. In Austria the de-Nazification process identified three or four different types of ex-Nazis, including those who were not party members but were close to these organisations. They were not Nazis, but opportunists. Some of these individuals later came to hold strong positions in the music business. Therefore, for years, this music remained unknown. Even Mahler was only rediscovered by Leonard Bernstein in the 1960s."
Simon Broughton first visited Terezin to make a radio documentary before the fall of the Iron Curtain. The visit gave him another angle on the music's neglect. "The communist government had been using Terezin as a monument against fascism," he says, "not primarily as a former Jewish ghetto."
He found the whole story fascinating from the start, "not just about artistic creation in terrible conditions, but the sheer quality of what was produced. Later, when everything was opening up in Czechoslovakia, access became easier and I returned to make a film."
One story that impressed him was that of Viktor Ullmann's opera, The Emperor of Atlantis, its libretto a none-too-subtle allegory of Hitler. "It went right up to its dress rehearsal before the Nazis realised what it was and put a stop to it," he says. Among other works that the inmates performed and that became hugely symbolic for them was the children's opera Brundibar by Hans Krása, written in Terezin and featuring on film during the weekend.
Greta Hoffmeister, one of the survivors who will speak at the Wigmore Hall, was 12 years old when she joined the Brundibar cast. "I was auditioned and chosen as the girl soloist, Aninka," she recalls. "I was very happy - my 'fee' was margarine and sugar. I sang it about 50 times. I was known for years not as Greta but as Aninka. The moral of the story is, if you unite you will overcome. We really enjoyed it. It was the only hours of normal childhood we had."
As well as offering a chance to hear astonishing music, the Wigmore weekend should help to scotch certain myths about Terezin - for example, the notion that the ghetto's cultural life was set up by the Nazis specifically to provide a smoke-screen for the evils of concentration camps. In fact, it was because they discovered such high-quality artistic activity in Terezin that the Nazis decided to make use of it. A propaganda film, The Führer Gives the Jews a Town, presented Terezin falsely as a model community, filled with culture and the adequately fed. The population was actually starving, but the Red Cross swallowed the disinformation whole.
If there is a lost genius to single out, it could be Gideon Klein, who was only 22 when he was deported to Terezin - later he died in the Fürstengrube camp. He had won a scholarship to the Royal Academy of Music in London in 1940, but the German invasion prevented his departure. Broughton considers him the most fascinating of the group. "He could easily have been part of the post-war musical scene of London," he says. "Now his music should be widely heard beyond the Terezin context."
Paul Watkins, cellist of the Nash Ensemble, seconds this, feeling that Klein's duo for violin and cello is among the finest works on the programme. "But all the music is so bloody good!" he adds. "It's vital to remind people of what happened, but it wouldn't be as powerful a weekend if the art didn't have the quality to stand on its own."