For three years, the Czech composer Pavel Haas was part of a creative powerhouse that helped sustain the inmates of the Terezin ghetto. Robert Cowan visited the former transit camp and met the man who is bringing Haas and other `degenerate' musicians back from the grave
`Every time I visit Prague, I discover yet another beautiful area that I never knew existed..." Record producer Michael Haas's words echo my own delight in this most picturesque of European cities. Haas escorts me from the brightly coloured, fairy-tale architecture of the Old Town Square to the more austere State Opera House nearby. We are about to hear the third and final concert performance of the opera Sarlatan (The Charlatan), the story of a travelling quack who operates on his one-time enemy, the monk Jochimus, and succumbs to paranoia. Decca is recording the opera for future release as part of its "Entartete Musik" (or "Degenerate Music") series, in which composer-victims of totalitarianism, and Nazism in particular, are resurrected for a new generation of listeners.

Sarlatan is the work of the Brno-born Czech composer Pavel Haas (no relation), who was sent to his death in Auschwitz in October 1944 after experiencing a surreal spot of creative respite in the Terezin ghetto-transit camp, some 60km north of Prague's city centre. Only hours before seeing his opera, I had been in Terezin myself, treading the weed-littered pathways of an 18th-century fortress town that was originally built by the Emperor Josef II in honour of his mother, the Empress Maria Theresa (hence its German name of Theresienstadt), and that is laid out - with cruel irony, given its later function - as a six-pointed star.

The drive from Prague, initially over cobbled streets, had taken us past rolling hills, an old monastery, a sugar factory and rotting, tumbledown bungalows. There were no road-signs to show us the way to the camp - until, just a few kilometres short of our destination, a stark hoarding to our immediate right announced "Terezin - Muzeum Ghetta".

The site itself is now dominated by a tall wooden cross and a crown of thorns, with 2,386 gravestones leading down towards a prominent Star of David perched on a mound of scull-like stones. The ghetto site nearby is a pretty, baroque-style garrison town, but the "small fortress" - where 10,000 or more inmates died - is blatantly a place of terror.

Beyond the grassy mote and entrance gate, the second archway pledges the all-too-familiar "Arbeit Macht Frei!". There is a guards' office, where elegant net curtains (now filthy) still hang at the windows, and a "show shaving room", where Gestapo officials impressed a Red Cross delegation with rows of taps, mirrors and sinks (now netted with hairline cracks). In reality, none of the taps were ever connected to the mains supply.

Memories of Wilde's Happy Prince were prompted by a trapped swallow hammering helplessly at the upper door-frame of the hospital block where, over 50 years ago, hundreds died of typhoid. There are the torture cells, a Kafka- esque underground passage (half-a-mile long) that leads to the "gate of death", the place of execution and the mortuary. The gallows are still standing, a tunnel nearby leads to mass graves, and only the sky remains unstained - save for the terror that one's imagination brings to it. Terezin's last prisoners left in August 1945, part of a savaged human legacy that was eventually dispersed among 39 separate countries.

By contrast, the ghetto town itself was host to an astonishing burst of artistic creativity, something that the Nazis were eager to exploit for propaganda purposes (they even made it the subject of a film, Der Fuhrer schenkt den Juden eine Stadt - "The Fuhrer Gives the Jews a Place to Live"). The "small fortress" museum houses a number of remarkable pencil sketches made at the time, many of which astound with their acute sensitivity to detail and human expression. Then there was Brundibar (Bumble-bee), a children's opera by Haas's compatriot Hans Krasa, performed in the camp itself by a cast that was constantly replenished as its young stars were systematically despatched to the gas chambers. Both Krasa and Haas entered Terezin in 1941, and both travelled to their deaths in Auschwitz on the same October day three years later.

Sarlatan itself dates from the late 1930s and has a decidedly Czech flavour: bright, tuneful and vividly atmospheric, sometimes reminiscent of Haas's teacher, Leos Janacek, sometimes of Korngold, even Hindemith. Though modestly attended, the Prague performance was enthusiastically received and the conductor, Israel Yinon, visibly grateful for such a genuinely appreciative response. Yinon, who is Israeli-born and now in his mid-forties, is tirelessly energetic. Some two hours after conducting Sarlatan, he walked from the State Opera to my hotel; he didn't actually reach me until well after midnight, and yet he was still eager to talk.

His first significant conducting engagements were in Germany, mostly with leading radio orchestras. "It is very hard for an Israeli to go to Germany," he tells me. "Some weeks after I arrived there, I started to think things out more deeply. My father's mother was shot in front of his eyes: he was just nine at the time. My mother was actually born in Israel, but when the Italians bombed Tel Aviv - in 1943, I believe - her father was killed. For him, even being in Israel couldn't protect him from the Nazis." Before Yinon left Israel, he met Ruth Elias, who, years earlier, had survived one of Josef Mengele's hideous medical experiments. "She had been in Auschwitz," Yinon explains, "and had decided to speak out about these things - although people at the time thought she was crazy and that she ought to shut up. She said to me, `Why go to Germany?' And I answered, with some embarrassment, that I wanted to start my career there. Then she told me about Krasa's Brundibar and later put me in contact with Sister Veronika in a Freiburg convent, who supplied me with a tape of the work and a starting-point for further research." Yinon notes that German music-lovers have an unavoidable "complex" about the Terezin composers - "and I understand why. There is a conflict with the past; then they have conflicts with me, and with themselves - it is all very complicated. But I refuse to judge them. It will take at least another two generations for things to change."

Producer Michael Haas adds that the Germans have, in the past, shown a certain scepticism towards the "Entartete Musik" project as a whole. "They have tended to think that, if the music had been any good, they would already have known about it," he explains. "But then Berthold Goldschmidt's work made them think again, while Braunfels' Die Vogel [a masterly operatic version of Aristophanes' The Birds recently issued as part of the series] marked another step forward..."

As to Yinon, further discoveries soon followed Brundibar and so did recording commitments, initially for Koch International (for whom he has recorded music by Terezin composer Vicktor Ullmann, creator of the camp's best- known musical memorial, the opera The Emperor of Atlantis), and now for Decca. "Michael Haas said to me, `Israel, suggest something good.' He trusts me a lot, which makes things harder for me. But I have to tell you that he made the decision to record Sarlatan in two minutes! I had already recorded the orchestral suite [for Koch] and when I played it to him, he looked at me and said, `This is a masterpiece, we must record it'."

It's interesting that Yinon thinks of the work as more "Czech" than specifically "Jewish". He observes a telling contrast between the Czech-inflected Sarlatan and the recently revived Betrothal in a Dream (also due for a Decca release) by Haas's Terezin companion, Hans Krasa, a Jew who belonged to the German minority in Czechoslovakia and who actually wrote his text in German. Yinon gave the German premiere of Betrothal; he also prepared the piano score. But his current range of interests extends beyond the ghettoed borders of "Entartete Musik" to contemporaneous works by non-Jewish Germans. "If I want to put this `forbidden' music into its proper context," he says, "I also have to present other composers from the same period. Viewed as a group, you might find that one composer emigrated, another stayed behind and a third was murdered by the Nazis. And yet all had something to say and, most important of all, we don't know their music." He talks of Heinz Tiessen and Eduard Erdmann in glowing terms, singing extracts from their works ("Erdmann's First Symphony is big music with six horns - a bit like Strauss!") and enthusiastically protesting Tiessen's apparent stylistic leap "from Strauss to Bartok".

Yinon has studied music theory and composition, but exactly when did he embark on his conducting career? He shrugs, then waves me to silence. "It is a secret," he says; "I have told no one ... but I will admit it to you. Tell me what you think: should I confess that I have been a conductor for only six years? I started in my mid-thirties, and that's very late. I had played accordion in a folk-band, worked for a psychological institute in the Israeli army, worked in a bank, guarded children in a boarding house..." No need to explain further. I'd watched him in action, heard his records, learnt some of his views, and there can be little doubt that few conductors on the current circuit are better qualified to serve what is, in a sense, the lost generation of 20th-century composers.