Sir Peter Maxwell Davies's monodrama Eight Songs For A Mad King is now seen as a particular stretch for an operatic baritone.
Young singer Marcus Farnsworth, who was highly praised for his performance in Mark Anthony Turnage's Greek, will be the latest to tackle its virtuosic demands when The Hebrides Ensemble begins a short tour with the first Scottish performances of the work in almost a decade on Monday.
But the composer wrote it with a very specific voice in mind, not a singer but that of South African actor Roy Hart, who had mastered a number of unusual vocal techniques, including the ability to sing chords.
"I though no-one could sing it they way he had," says the composer, "but recently I heard it sung by a lady in Virginia who had a very similar skill."
Max, as he is known by all, is not about to insist that there is only one way to tackle the demanding score, which he based on tunes from a musical box owned by George III which the deranged monarch had attempted to teach to his pet finches.
"I wrote it very quickly with great drive – I think I had six weeks to do the whole thing," he remembers. " But I was burning the candle at all three ends back then."
The work was premiered in 1969 with the composer conducting his own pre-Fires of London group, the Pierrot Players, at the Queen Elizabeth Hall – and its long-term popularity would not have been predicted.
"It caused huge controversy, with people shouting out 'rubbish' and 'shut up'," says Max. " So it is very nice that people are doing it now, with great understanding."
The Hebrides Ensemble production, which goes on from the Old Fruitmarket to play Inverness, Edinburgh and Tain, is directed by Ben Twist, former artistic director of Contact Theatre in Manchester and associate director at Edinburgh Traverse, and is fully staged with the musicians in cages to symbolise their role as the birds. The performance will be the culmination of a programme that also includes music by Xenakis, George Benjamin and Thomas Ades, played by a sextet of some of the finest musicians working in Scotland.
Max, on the other hand, has been working everywhere but. On the day we speak he is about to journey home to Sanday in Orkney for the first time in many months. He has been living working in Italy, creating a new piece for Claudio Abbadio and his Orchestra Mozart for performance in Bologna. And he has been teaching in Washington, where students staged their own production of Eight Songs For A Mad King and the composer was most gratified by the audience reaction.
Its technical difficulty means that it is not the most often-performed of Max's short operas. That honour goes to The Lighthouse, which Perth Festival regulars English Touring Opera have out on the road at the moment (it is at Snape Maltings in Aldeburgh tonight) and which has had "hundreds of productions". At the St Magnus Festival in 2000, the composer said that Mr Emmett Takes A Walk, which premiered then, would be his final chamber opera, but he went on to collaborate again with its librettist, opera director David Pountney, on Kommilitonen! for the students of the Royal Academy in London last year.
That tale of student activism was later produced by students at Juilliard in New York, and – to the composer's everlasting delight – taken to Zucotti Pary as part of the Occupy protests, an example of opera being taken out on the streets that puts him in the company of Giuseppe Verdi.
Of course, it turns out that he is still not finished with opera and has a new work coming up in Germany. In Scotland, we shall hear a piece he has written for the 40th anniversary of the Scottish Chamber Orchestra in 2014, the year of his own 80th birthday, which will be marked, amongst other events, by the premiere of his 10th Symphony by the London Symphony Orchestra.
But immediately there is the new Eight Songs. "I hope I get to see it, because I owe the Hebrides a huge debt. They are one of the great glories of Scotland."
Eight Songs For A Mad King is at the Old Fruitmarket, Glasgow on Monday; Eden Court, Inverness on Tuesday; The Jam House, Edinburgh on Thursday; and St Duthus Collegiate Church in Tain next Friday.