Richard Wagner – or, rather, the Wagner dynasty – is in the news again, with intrigue about who in the family will inherit the directorship of the 131-year-old Bayreuth festival, created by the composer in the theatre built specifically for the performance of his work. Wagner occupies music and opera lovers as no other composer does. Some unequivocally worship him, their trips to Bayreuth akin to pilgrimages. Others revile him. Many can do both at once, separating Wagner the composer from Wagner the self-obsessive, a man who, though often penniless, lavishly spent others’ (particularly the adoring Ludwig II of Bavaria’s) money, who freely exercised his considerable libido, who demanded adoration and who held some highly suspect views, on, for instance, Judaism. The music itself requires much of us: endless uncomfortable hours in the opera house, with outrageous demands upon not only time but concentration. Many meekly enter his world on his terms – and gasp in amazement.

What makes this man and his work so important is, essentially, his reforming spirit. He wanted to purify opera, to return to something like the concept envisaged by its creators in the late 16th century, one aimed at resurrecting the principles of Greek drama. So, he dispensed with “number opera”, with its distinct arias, ensembles, choruses and recitatives, and came up instead with something labelled the Ges-amtkunstwerk, the “total art work”. In the Gesamtkunstwerk, everything – orchestra, singers, scenery, acting; even, ideally, the theatre itself – was a vital, inseparable part of the whole. In this way, Wagner was able to express complex psychologies. His was not the all-action opera of the French and Italians, but an internal drama. It was a big idea, one that, despite the limitations of the literal interpretations that were the order of his day, has given today’s interventionist directors huge opportunities. A Ring production can have a Marxist leaning, since one message of the opera allies itself to Proudhon’s assertion that property is theft. It can be inspired by the nihilism of Schopen-hauer, since all comes to naught. Or it can be psychoanalytical, a Jungian examination of the mind. And so on. Fertile ground for continuing controversy.

The music is unique both in its epic scale and in its sound world, structured in vast paragraphs and unified through the device of the leitmotif, a snippet of music – a chord, a phrase – that signifies thought, character, mood or symbol. These snippets may not be consciously recognised and labelled, but their presence and interreaction subliminally convey meaning and nuance. Wagner’s role in the evolution of music is crucial. His mature language is a rich-textured, multi-layered sound, full of detail but never confused. He uses a large orchestra, not just for its brute force, but for the range of colours it offers. And he pushes the bounds of tonality to the limit. Undoubtedly, the most talked-about chord in all music is the so-called “Tristan chord”, from Tristan und Isolde. Isolated, it doesn’t seem to be alluding to any key. And when Wagner resolves it, he lands on another chord that leaves the music lingering, suggesting longing, or maybe ecstasy, or maybe death prolonged. It is just a small step from here to the atonal world of Arnold Schoenberg and others.

Indeed, without Wagner, there would have been no Schoenberg, no Richard Strauss, no Gustav Mahler – not, anyway, as we know them. Debussy, for all his railings against Wagner, took on the German composer’s idea of opera as an integrated art form and a window onto the innermost psyche in Pelléas et Mélisande.

So, Wagner opera remains in heavy demand whenever it’s in town, which is often. Keith Warner’s finally complete production of The Ring at Covent Garden, to be staged three times this autumn, is so oversubscribed that patrons are being sold tickets for the rehearsals. At Bayreuth, the waiting list for a ticket stretches back 10 years. People return to Wagner again and again, not simply to see yet another production or to hear a particular singer, but because they know that even if it’s the wrong singer for them and the 10th time they have seen the staging, they can be pretty sure another layer will reveal itself, another thought stirred.

What about those uncomfortable connections with the Nazis, though? Wagner, it is true, was more or less adopted as the quintessential Nazi composer in the early 1930s. Hitler adored his music. But that was hardly the long-dead composer’s fault. Another problem was that Winifred, the British-born wife of Wagner’s homosexual son, Siegfried, was close to the Führer. In 1933, it was even rumoured that the pair were to marry. This relationship is fascinatingly charted in Jonathan Carr’s forthcoming book The Wagner Clan, and, in a rather different way, in AN Wilson’s quasi-historical new novel, Winnie and Wolf.

Winifred inherited the directorship at Bayreuth on her husband’s death, and thereafter Hitler began subsidising Bayreuth’s coffers more generously even than Ludwig II had done. Bayreuth in turn mounted productions of Die Meistersinger that became ever more tub-thumping celebrations of the glorious fatherland. The institution was “Nazified”. DeNazification was attempted after the war, by replacing Winifred with her sons, Wieland and Wolfgang. Despite radicalisation of production styles, it has proved hard to rid Bayreuth of every trace of bad odour as long as it has remained in family hands.

There is no question, of course, that Wagner was resolutely antisemitic, becoming more so as he grew older. But how much that had to do with pure prejudice and how much it was down to his resentment that the Jewish composers Meyerbeer and Mendel-ssohn held artistic sway in Paris and Germany at times when Wagner was eager to make a name for himself in those places is debatable. Certainly, in his notorious 1850 essay Judaism in Music (penned under a pseudonym), he is ready to characterise all Jewish music, and the music of these two men in particular, as superficial. That was an unfair judgment, particularly upon Men-delssohn. But whether he believed also that the only solution to perceived Jewish economic and political dominance was their physical annihilation is another matter. He was, after all, a libertarian revolutionary, forced to flee Dresden in the suppressed 1849 uprising there, and he numbered many Jews among his friends. But the Jewish issue is not one to be belittled, and it is an aspect of Wagner that has guaranteed he will remain for ever a talking point.

Indeed, Wagner’s antisemitism and his association with the Nazis – or, rather, their association with him – still means that there are many who cannot bear to hear his music. Until fairly recently, it was impossible to encounter it in the state of Israel, until that great Wagnerian Daniel Barenboim decided to throw his considerable moral weight behind the matter. And as that devout Wagnerian Michael Portillo pertinently asked in a New Statesman article a couple of years ago, why is it that a love of Wagner is so often taken to signal right-wing, antisemitic tendencies when a love of Richard Strauss, at least on occasion a Nazi sympathiser, signals only the height of good taste?

Love the music or not, Wagner cannot be ignored. Larger than life in his own lifetime, posthumously he gets no smaller. The Bayreuth feuding might be what’s in the news, but it’s the art that perpetuates the reputation. And whether it’s young Katharina Wagner who takes the reins of the family business, or her half-sister Eva, or indeed her cousin Nike, one cannot change the reason for or the importance of Bayreuth’s existence.

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