Crossposted from European Tribune.
They say his music boosts your IQ and makes cows produce more milk. I don’t know if this is true, let alone whether he is the “greatest” composer ever. But the unbelievable legacy of the world’s only posthumous pop star speaks for itself! 
In a book cheesily entitled Mozart and the Wolf Gang, written for a previous anniversary, Anthony Burgess — who himself was trained as a composer — muses thus:
One aspect of Mozart’s greatness is a superiority in disposing the sonic material that was the common stock of composers of his time. Sometimes he sleeps, nods, churns out what society requires or what will pay an outstanding milliner’s bill, but he is never less than efficient. Clumsiness is sometimes associated with greatness: the outstanding innovative composers, like Berlioz and Wagner, are wrestling, not always successfully, with new techniques. Mozart is never clumsy, his unvarying skill can repel romantic temperaments. ‘Professionalism’ can be a dirty word. He touched nothing that he did not adorn. If only, like Shakespeare, he had occasionally put a foot wrong — so some murmur. He never fails to astonish with his suave or prickly elegance. (144)
We often forget how recent is Mozart’s place in the trinity of “all-time greatest,” alongside Bach and Beethoven. It was secured in the post-WW2 era, before which he was mostly thought of as an opera composer. Also, it owes deeply to conductors like Böhm and von Karajan striving to make of Mozart what he isn’t: a Grand Heroic Symphonist in the Teutonic mould. It’s funny to hear these recordings now, when more authentic performances informed by historical research are the ideal. But it says a lot about this music that it remains so stylish even when shoehorned into an alien romantic form.
Burgess concludes:
As a literary practitioner I look for his analogue among great writers. He may not have the complex humanity of Shakespeare, but he has more than the gnomic neatness of an Augustan like Alexander Pope. It would not be extraordinary to find in him something like the serenity of Dante Alighieri. If the paradisal is more characteristic of him than the infernal or even the purgatorial, that is because history itself has written the Divine Comedy backwards. He reminds us of human possibilities. Dead nel mezzo del cammin di nostra vita he nevertheless presents the whole compass of life and intimates that noble visions only exist because they can be realised. (147)
Today the world is celebrating Mozart’s 250th anniversary. Far better than fireworks is the exuberant final movement from the “Jupiter.”
Update: downloads now closed.