Beethoven didn't only achieve fame posthumously. In his irascible prime, he was already the most celebrated composer in the world, and his Ninth Symphony, with its "Ode to Joy", has kept the pot on the boil ever since. It was a sensation when it premiered in Vienna, and its after-life has been extraordinary, serving in the 19th century as the anthem for proto-Marxists, French republicans and German nationalists, and in the 20th for both the Nazis and their Jewish victims in Auschwitz.
The "Ode", which has been sung at every Olympic Games since 1956, was also adopted as an anthem by Ian Smith's white-supremacist regime in Rhodesia. In Anthony Burgess's A Clockwork Orange it stood for private criminality and public terrorism, and it was what Leonard Bernstein chose to conduct - with an orchestra symbolically drawn from six nations - when the Berlin Wall came down.
As an American critic once put it, we all live in the valley of the Ninth: no other work has been all things to all men. And no other composer remains so idolised. Next month, without even the justification of an anniversary, Radio 3 will clear its schedules to offer wall-to-wall Beethoven for a week, while BBC television embarks on the biggest retrospective it has ever mounted on a composer. This is so remarkable that it's worth asking why.
The stock answer is that we thrill to the way Beethoven's sufferings - deafness and a thwarted love life - fuelled his creative triumph. That's fine as far as it goes, but it doesn't explain Beethoven's unique ability to compel us to hang on his every note. It might be that a combination of musical, political, and economic factors produced exactly the right situation to draw out his genius. But not even that explains his power over us. The key, I believe, lies in the realm of psychoanalysis. For Beethoven was, in important respects, not so much sad, as mad.
He was a solitary, monosyllabic child, who took refuge in a dream-world to escape the miseries of the real one: neighbours saw him weeping under his father's cruel musical tutelage. And his father was a drunk: when Beethoven's melancholic mother died in his 16th year, he was forced into surrogate parenthood of his younger siblings.
More significant was the fact that he grew up believing he was illegitimate. Like Salvador Dali, he lived in the shadow of an elder brother of the same name, who had died in infancy: Beethoven believed that his own birth certificate actually belonged to this other Ludwig. When he was 12, he wrote a song "An einem Saugling" (suckling), which began with the words: "You still do not know whose child you are." Even in his middle years he claimed not to know his real age, and he wove a fantasy - which he encouraged others to believe - that he was of noble birth. This suited both his aristocratic view of himself, and his contempt for his father. But denying the truth always comes at a price, and Beethoven paid his in the form of mid-life madness.
The principal symptom of this madness was Beethoven's manic determination to wrest custody of his nephew Karl from his brother's widow, in a tug-of-love that he masochistically dragged through the courts. The first psychoanalytical study of this case asserted that Beethoven was an authoritarian sadist transferring his homosexual feelings for his younger brother Caspar on to his nephew Karl, whom he tried to rescue from the "fatal claws" of his evil mother. Karl, who spent 10 years as a rebellious prisoner in Beethoven's house, finally tried to shoot himself.
A more cogent analysis comes from the American musicologist Maynard Solomon (who has also solved the riddle of the "Eternal Beloved" to whom Beethoven penned his famous missive). Solomon argues that the dead Ludwig was the fantasy-twin whom Beethoven desperately needed to keep alive, and that the forcible appropriation of his nephew Karl was a desperate symbolic ploy to reincarnate the dead brother. Only when Karl attempted suicide did Beethoven relinquish this fantasy. But as Solomon points out, some of Beethoven's most haunting music is dedicated to this "twin", who represented a magic doubling of his powers. That is the magic which reaches out to us, as his subconscious makes contact with ours.
Meanwhile, Beethoven's productivity was brought to a halt by his eventual realisation that he would never found a family of his own, and that he was in this respect impotent. Add to that his deafness - what could be worse for a musician? - and you get some idea of the troubles that threatened to overwhelm him. Yet despite the explosion of despair in his Heiligenstadt Testament - "Oh you who consider me misanthropic... you do not know the secret cause" - Beethoven's musical powers were scarcely impaired by his deafness: in one sense, it was merely a continuation of the metaphorical "deafness" into which he'd retreated as a boy. All his life he lived in a world where the loudest sounds were those inside his head. Magic saved him once more, as he turned this disability into superhuman strength, and groped his way, one masterpiece at a time, into the transfigured world of his late works.
"If I were to hear that music often, I would always be very brave": with these words, chancellor Bismarck put his finger on Beethoven's unique capacity to inspire heroic deeds. And philosophers as well as politicians fell under his spell, as was Beethoven's explicit intention. "I despise that world," he wrote to a friend, "which does not intuitively feel that music is a higher revelation than all wisdom and philosophy." To the Romantic movement that was then dawning, an artist was a quasi-religious prophet, and Beethoven was the ideal exemplar.
"You ask me where I get my ideas," Beethoven wrote in one of the conversation-books through which he communicated with his friends. "I cannot answer this with any certainty: they come unbidden. I may grasp them with my hands in the open air, while walking in the woods, in the stillness of the night, at early morning. Stimulated by those moods that poets turn into words, I turn my ideas into tones, which resound, roar, and rage, until at last they stand before me in the form of notes."
"Beethoven is not a man," wrote Bizet, "he is a god, like Shakespeare, like Homer, like Michelangelo." For Liszt, Beethoven's music paralleled "the pillars of smoke and fire that led the Israelites through the desert... so that we may march ahead both day and night."
Beethoven's last words were allegedly "Comoedia finita est" [the comedy has ended], but he wrote a more fitting sign-off in one of his conversation-books: "The moral law within us, and the starry heavens above us." Yes, this was a visionary who encompassed the universe.
The Beethoven Experience, on Radio 3, BBC2 and BBC4, runs from 30 May to 2 JulyReuse content