For anyone with a sense of history, especially music history, the Vienna telephone directory makes interesting reading. Names encrusted with the past – Lichnowsky, Waldstein, Kinsky, Esterhazy, famous for their palaces, their wealth, their patronage of great composers – live on, not so grandly as two centuries ago but with surviving chic as pillars of the central European Hochgeboren. Still in business, still accumulating wealth and still occasionally giving it away to latterday equivalents of the Haydns, Beethovens and Mozarts that their ancestors provided for. Noblesse oblige and all that.

Then there are the Metternichs. “And when you see this name, what do you think?” asked the current Prince Metternich-Sandor, otherwise known as Tassilo, as he steered me through the large, draughty rooms of his country pile Schloss Grafenegg, an hour’s drive from the capital.

“OK, you think the famous chancellor, the statesman who sorted out post-Napoleonic Europe at the Congress of Vienna. But then not so happily you think repressive regimes, secret police. Whenever our name comes up in Austrian newspapers it’s usually to complain about something being ‘a Metternich-like policy’. If I were a politician, which I’m not, they’d have a lot of fun with me. But of course they do anyway. I was working in Hungary recently and was told: ‘We’re not sure about this. The last time we had a Metternich here to organise things it caused a revolution.’ It’s quite a past I have around my neck, no?”

For musicians, though, the take on Metternich is more specific. The original chancellor – Tassilo’s great x 3 grandfather or great x 4, depending on how you trace the line – turns up in the chronicles of music not as a patron but a threat. He was the man who, through his Viennese police spies, made life difficult for Schubert’s circle of young headstrong radicals, periodically rounding them up on suspicion of subversive activity and even dispatching one of them to prison. “It doesn’t sound good, does it?” says the current prince, accepting that his ancestor was “no fan of music”.

But music has a way of striking back. And this month it does so emphatically when the Prince’s latest venture on the Grafenegg estate opens for business. It’s a concert hall, or rather, a concert auditorium, designed to hold state-of-the-art open-air concerts for audiences of up to 5,000 at a time without amplification. Just the natural acoustics that serious classical musicians expect.

Part of a €25m project that will eventually include an accompanying enclosed auditorium, it had a trial run back in June and launches properly on August 23 with a festival that involves some of the biggest names in the classical world, including Renée Fleming, Alfred Brendel, Valery Gergiev with the LSO, Zubin Mehta with the Israel Philharmonic, Ian Bostridge... The list runs on, co-ordinated by the veteran Austrian pianist Rudolf Buchbinder, who acts as artistic director for the whole project.

“It’s not the first time we’ve had music at Grafenegg,” says the prince. “There were concerts in the Schloss for decades, organised by my father and we even had Brendel here before. But it was on a far smaller scale than we’re planning now and never exactly comfortable, as Brendel discovered on that previous visit. He wanted to stay overnight in the Schloss. We explained that no one lived here any more – my house is a separate building on the estate – and that there were no amenities. It’s a museum. But he insisted, so we created a bedroom for him. And by the middle of the night, as the wind howled through rattling window panes, and there was no warmth, no room service, no anything, he regretted it, though without lasting ill will, which is why he’s coming back. We now have a rather nice designer hotel down the road.”

The rattling emptiness of Schloss Grafenegg is, in fact, the very reason for the prince’s entry into big-league concert management. And the reason for its emptiness is a familiar one among the Austro-German aristocracy: the second world war.

Essentially a 16th-century moated castle, spikily re-gothicised in the mid-1800s after one of the family saw Sir Robert Walpole’s house at Strawberry Hill in Twickenham, west London, and fell in love with it, Grafenegg fell into the hands of the Metternichs through one of the complicated matrimonial transactions that reduce Tassilo to counting on his fingers when he tries to explain his descent from the chancellor.

“The simplest version is that the chancellor had three wives, in succession naturally. One of them married a Hungarian count called Sandor who was a madman – in England you’d call him eccentric – and died in an asylum but not before they’d had a daughter, who then married her half-uncle. Which you’re not supposed to do but there it is. So you have the grand-daughter of the chancellor’s first wife marrying the son of the second wife. You follow?”

I do, but lose the plot by the time we get to Tassilo’s father being given for adoption to his great-aunt: a manoeuvre Tassilo describes as “what you did in Central European families where there were too many daughters and not enough sons”.

In any event, Tassilo’s father ended up with Grafenegg and lived there more or less happily until the outbreak of war. After a brief spell in uniform, he was discharged from the military (like others of similar aristocratic background following a decree issued by Hitler known as the Prinzenerlass) and sent off to manage agricultural estates near Hanover. With the war over, Lower Austria, the territory around Vienna, fell to Russian occupation and Schloss Grafenegg was taken over as a Soviet military headquarters.

“In 1955 he got it back but in a dreadful state and empty because the Russians had carried everything off to Moscow: 22 wagons of furniture, pictures, books, the lot. The only thing they left, rather charmingly, on the library shelves was a 20-volume set of the lives of Lenin and Stalin. Their parting gift.”

Was nothing done to get it back?

“No point, although the Russians clearly thought we’d try. Some years ago a Russian cultural delegation came here for a few days to discuss concert proposals and there was one guy who never said a word: just sat with an angel-faced smile in total silence. I assumed he spoke no German. But on the last night we all went out to for a Heuriger evening [an evening of drinking wine from the most recent harvest] and suddenly Angel-face opened his mouth. Perfect German. And from what he said I’m sure his role in this delegation was to find out if we were planning some kind of legal action.

“The truth is my father just resigned himself to the loss of everything and set about trying to restore the Schloss. But not as a home. It’s not exactly cosy, is it? I mean, you wouldn’t want to live here – although it was fun for me to run around in as a child.”

An ultra-urbane, chain-smoking, Mercedes-driving European high-born of the new breed who speaks English with just the barest trace of an American accent, Tassilo was born soon after Grafenegg’s recovery and brought up in a yellow-painted villa on the other side of the moat that would once have housed the family’s land agent, or some comparably bourgeois functionary. From there, with what eventually became four brothers, he watched the restoration of the Schloss, part-financed with government money on the grounds of architectural rarity.

“You find plenty of 19th-century historicism in Vienna, in the Ringstrasse palaces, but not so much in the Austrian countryside. And you especially don’t find things like this,” says Tassilo, opening a hidden door that leads into a balcony above a jewel-like Gothic chapel with the vaulting painted in a lurid blue.

“We didn’t like the blue but it’s apparently authentic and the government said, ‘we’ll pay.’ So we said, ‘Paint it any colour you want.’ But it was made clear that they weren’t going to spend all this cash on a holiday home for the Metternichs. The deal was that we’d open up to the public, and use the estate for cultural events. So that’s how we get today to the new concert auditoria in the grounds, and to our festival.”

Legally, the auditoria and festival are a joint venture between Tassilo and the federal state of Lower Austria. And if it seems extravagant for Lower Austria to be throwing so much money at two new music venues barely an hour from Vienna, which has no shortage of such things, the explanation is partly political. The state of Lower Austria geographically includes Vienna, which used to be the state capital as well as the national one. But 15 years ago the state capital moved to St Pölten, and since then Lower Austria has been keen to establish a cultural identity of its own – with a more visible platform for its own state orchestra, the Tonkünstler, a venerable ensemble, if historically outclassed by the Vienna Philharmonic.

In future years the Tonkünstler will be resident at Grafenegg throughout the summer, with guaranteed appearances in the high-profile August festival. “So this open-air theatre meets many needs,” says Tassilo as he walks me round its bizarre exterior which erupts out of the earth like a piece of concrete origami. “It will provide a completely different kind of concert experience to the halls in Vienna. A sort of European Tanglewood,” he adds, referring to the open-air summer home of the Boston Symphony in the US. “And as you see, we haven’t tried to hide it. It makes a certain statement, no, against the architecture of the Schloss?”

A director of Environmental Resources Management, an international environmental consultant, in another, less ancestral life, the prince appreciates the pros and cons of architectural statements; but he argues passionately for this one and for the thousands of people it will draw to the Grafenegg estate.

“This is a fantastic opportunity to sell classical music at the highest level to the widest public. The ticket prices will be cheap – as low as €6 if you sit on the grass. The atmosphere will be relaxed, it’s ideal for young people, for families with children like mine (aged two, four and six, the products of his marriage, from 1999, to Clarissa, Countess of Törring-Jettenbach) who are too young to sit still and behave like you’re meant to in a concert but who love clambering around the structures of a building that, when it isn’t being a performance space, makes a very fine playground. Things a conventional hall like the Musikverein couldn’t deliver.”

And would the chancellor approve? “I don’t know. But he didn’t approve of Schubert and his friends having a good time. So maybe he’s not the test.”

Promoters, patrons and players

Classical concerts are more likely to lose money than make it, which is why they function largely in the world of public funding – organised by, or in conjunction with, state-run venues, charities, trusts or broadcasting organisations. But there has always been a role for private promoters, latter-day equivalents of princely patrons who held concerts in their palaces. It’s an industry largely based in London, led by names such as:

Harrison Parrott

Run by urbane, silver-haired industry guru Jasper Parrott, with strong connections in the Far East where it project manages major festivals and tour orchestras such as the Czech Philharmonic, Cleveland and Concertgebouw. Also co-ordinates the prestigious International Piano Series at London’s South Bank, and has just set up an associate series in Istanbul that starts this autumn.

Askonas Holt

Currently running an international touring project for the Orchestra of the Age of Enlightenment with Ian Bostridge and a similar tour for hot young conductor of the moment Gustavo Dudamel with his extraordinary youth orchestra from Venezuela. Projects for next year include Barenboim playing all the Beethoven sonatas at the Festival Hall, and a dance season at the London Coliseum.

IMG Artists

Massive organisation, based in New York and represented throughout the world. Strong in big, popular mass-market events that sometimes go awry (like the open-air concerts at north London’s Kenwood House currently in abeyance because they upset the neighbours, not to say the wildlife). Also running large-scale festivals in Tuscany, California, Florida and, from October, Singapore.

Van Walsum

Founded by a Dutchman but based in London. Organises concert tours for a wide range of orchestras and ensembles from the Los Angeles Philharmonic to Westminster Abbey Choir. Has just been shepherding the Bach Collegium of Japan around Germany and the UK.

Victor Hochhauser

Formidable couple based in London, Victor and Lillian Hochhauser have been bringing Russian artists such as Oistrakh, Richter, Rostropovich and whole companies such as the Bolshoi and Kirov to the west for half a century – all of whom were only too grateful for the hard currency. They also run projects with La Scala Milan.

Konzertdirektion Schmid

Based in Hanover and probably the leading promoter in the German-speaking world, organising festivals and US orchestral tours in mainland Europe.

Opus 3 Artists

Brand new name for ICM (International Creative Management). Still based in New York, it traces its origins back to Sol Hurok, paragon of hard-nosed 20th-century promoters who sold classical artists like fairground attractions, with flashing lights and no shame. Many of the greatest names loved him, possibly because he earned them more than anybody else.

The Grafenegg music festival runs from August 23 to September 9