It really should have been Beethoven who wrote his funeral ode. At his death at Missolonghi in 1824, Lord Byron was the most famous name in Europe: enemy of tyranny, apostle of freedom, metaphysical rebel, the ‘pilgrim of eternity’, and he had died taking up arms for those ideals. At least, that was the story.

By 1824, however, Beethoven was long past his days of writing music for heroes – though the composer of 15 years earlier might well have felt moved to rustle up something turbid and noble along the lines of his Egmont and Coriolan overtures. You feel nobody would have been more amused than Byron himself when the lament was duly composed, not by the Viennese Titan (and the poet would have found that absurd enough, to be sure) but by his own secret blood-brother, Gioachino Rossini, whose tunes (he particularly liked Rosina’s aria ‘Una voce poco fa’ from The Barber of Seville) Byron would Woosterishly whistle in his bath.

Rossini’s vividly Italianate ode (‘Ahi! Non è più quel grande!…’) would have had Byron snorting into his Marzimino all right. A lachrymose tenor – sung by Rossini himself at the first performance – sobs and eulogises over a chorus of emotionally devastated poetry-lovers, a heavenly harp beguiles the sombre chug of the orchestra. Best of all, this took place in London – to be precise, at Almack’s in St James’s – which Byron had escaped eight years earlier, in an England uniquely resistant to the appeal of the disgraced, renegade, Napoleon-worshipping poet, and whose manners, ruling class and weather he had relentlessly abused from exile. (After all, he was really a Scot.)

It’s nice to imagine that the 32-year-old Gioachino Rossini, on a lucrative six-month jolly in England, was kept up to speed on all the amusing ramifications as he performed the ode in June 1824 to the stiff-necked, grudging London ton. He was one of very few who could rival Byron for celebrity – Stendhal’s puppyish biography calls him Europe’s new conqueror, the new Napoleon – and, like the poet, his comic works reflected the distanced, ironising despair felt by civilised Europeans as all the idiotic old anciens régimes, which they had dared to hope had been swept away for good, redescended on the continent like vampiric spiders after Waterloo.

Byron’s political and cultural influence would persist in Europe for generations, providing excellent copy for artists, as well as sinew-stiffening inspiration for revolutionaries and freedom-fighters: the Decembrists, Kossuth, Mickiewicz, Mazzini, d’Annunzio, Trotsky. And yet, when you survey the products of the creative mania he fomented, from Delacroix’s lurid Death of Sardanapalus (1827) to Tchaikovsky’s tormented Manfred symphony (1887), you soon begin to discover strange divergences – plenty of ‘Byronism’, to be sure, but somewhat less in the way of actual Byron. Delacroix himself is a fine example: instead of Byron’s intimate suicide pact between the sensitive Assyrian king and his beloved Myrrha, the painter slathers on an elaborate fantasy of Oriental savagery, sex and luxury, naked concubines in various attractive poses having their throats cut, piles of jewels and expensive cloth, horses being dragged towards the nicely upholstered funeral pyre, the terrifically bored king himself evidently failing to derive much joy from the impressive scene.

The great thing about Byron, if you were a painter or composer hunting around for inspiration, was that there were so many versions of him available – a bonus on top of the way he so perfectly captured the romantic disillusion of the age, the double death of the idealism that had expired in Robespierre’s bonfire of the Enlightenment, followed by the snuffing of the Napoleonic flame. And a number of these Byron models were based in some sort of reality: the disaffected Childe Harold, prototype of the Byronic hero, moodily kicking about mountains and battlefields; the next-level alienated introvert Manfred, with his nameless sins and orotund hectoring-contests with spirits from beyond the grave; the druggy libertine, the poster-boy of fashionable rebellions, the high priest on the beach committing his friend Shelley to the flames, the origin of the Vampyre. Byron’s avatars populated a marvellous artistic cloakroom with ready-to-wear costumes hanging from every peg.

And really the handiest aspect of the myth, or myths, was that you hardly needed to actually read the poetry before getting down to work. In fact, that might have been quite a drawback – for God’s sake, you might have to rethink all the things you’d taken for granted, the accretions of legend provided by your artistic forebears piggybacking on his memory.

There could be no better example than Hector Berlioz’s ‘what I did in my holidays’ symphonic poem of 1835, Harold in Italy. Purportedly based on the last Canto of Byron’s long narrative poem – which ‘burning poetry’ Berlioz claimed he had feverishly read in a confessional in St Peter’s, where he had fled the Roman heat – the music is actually a reverie on the Abruzzi countryside where the composer had wandered, its highly subjective solo viola ‘a melancholy dreamer in the manner of Childe Harold’, the association with Byron really no more than an opportunistic marketing gimmick, plus a bit of regulation wish-fulfilment and shoring up of the composer’s own virile credentials, in the final scene of a bandits’ orgy.

This became the standard operating procedure for composers aiming to hitch a ride on the tail of the Byron comet. Now that pretty much everyone was a gloomy romantic, heartsore, more or less scornful of humanity in general, it made perfect sense to semaphore some kind of Byron reference, dangling the hope in front of your celeb-worshipping public that a bit of the sexy, borderline demonic Byron magic would rub off, even if (as in the case of Franz Liszt’s piano pieces Années de pélerinage) you had merely tagged a few impressionistic landscape scenes with epithets from very roughly appropriate bits of poems.

Music that genuinely engaged with the real Byron and his poetry was actually passing rare. Robert Schumann, the most literary of composers, was sufficiently impressed by the tormented Manfred to write stormy incidental music for the unstageable play (I heartily recommend the Thomas Beecham recording, magnificent and preposterous, with impossibly the spy declamation by the actors), which, in addition to its own febrile merits, boasts the nearest thing we have to that Byron Overture that Beethoven never wrote, full of turbulent defiance and dauntless nobility. Tchaikovsky’s Manfred symphony of 1886 also sticks close to the text, though the composer’s characteristic urge for self-revelation bursts through a good deal, and despite his obvious identification with Manfred’s erotogenic torment (Manfred’s thing with his sister Astarte mirroring Tchaikovsky’s guilty love for his own nephew), he never sounds all that comfortable in the heaven-defying hero’s skin – and redeems him most un-Byronically in the end.

The closest we ever get to seeing the poet himself on stage must be Heinrich Marschner’s opera Der Vampyr of 1828, derived from the story that John Polidori lifted from Byron’s own yarn from that Geneva fright-night when Mary Shelley also came up with Frankenstein. Polidori called his vampyre Lord Ruthven – taking the name from the exceptionally undisguised villain of Lady Caroline Lamb’s novel Glenarvon of 1816, wherein she exacts melodramatic revenge on the poet who had loved and left her. Marschner’s opera is considerable fun, juggling the proto-Hammer Horror of Weber’s Der Freischütz style with jovial German folksiness, and effectively conveys the information that Byron was not brilliant boyfriend material – plus entertaining metaphors about the blood-sucking nature of the aristocracy, for those inclined to look for such messages. Marschner was a useful model for Richard Wagner’s later Flying Dutchman, an instantly recognisable morose loner, a maritime Manfred roaming the seas in search of victims or redemption (take your pick, ladies).

So much for the myths and pret-a-porter versions. What about the true, the actual poetic Byron – the jaundiced, scurrilous, amused narrator of the great ottava rima satires Beppo, The Vision of Judgment and Don Juan? You seek in vain. But imagine what fun a mischievous Rossini could have had with selected scenes from Don Juan – or even one of our own cowpat crowd, Ralph Vaughan Williams and co, a few score years later. Yet there’s nothing but silence: as the 19th century descended from Regency japes to Victorian propriety, poetry was supposed to be earnest and profound, and the later, true Byron lost out to the properly ‘poetic’ Coleridge, Keats, Shelley and their progeny.

But there is one literary monument, later turned into an opera, which shows a genuine and affectionate reaction to Byron the poet, the man who worked through those fruitful youthful poses of furrowed-browed outsiderdom to the disenchanted but jaunty, accepting, actually great-spirited author of Don Juan: Alexander Pushkin’s verse novel Eugene Onegin of 1833. Pushkin, an astute critic as well as a great poet, completes the Byronic circle by writing about a wannabe Byronic hero – Eugene, ‘a Muscovite in Harold’s garb’ – through the eyes of someone very like Juan’s narrator, who views this peculiar creature with considerable scepticism. Eugene is really nothing but a callow poser. Similarly, Juan’s amused disdain makes it impossible to do anything but laugh at Harold and Manfred.

The truth is that Byron’s outgrowing – and implied ridicule – of Harold and co was a bit embarrassing for those who had gone to such lengths to don that garb. And so beyond Pushkin, the 19th century studiously ignored the great liberal epic Don Juan, the most genuinely Byronic work of all. And thereby, they all absolutely missed the point: it was the Byron of Juan, not of Harold, who did the ultimate Byronic thing, who went to Greece to unite and inspire the fighters in the war of independence. That’s right: the jokester who pretends to care for nothing, to satirise the world – he was the real champion of freedom, the implacable hater of tyrannies… and the master of irony, who would most definitely have thoroughly enjoyed this final one.