A few years later, Hans Christian Andersen wrote down Thorvaldsen's account of the sitting: "Byron sat down in front of me, but at once began to assume a quite different expression from that which he normally wore. 'Now, will you please sit still!' I said. 'You mustn't put on those airs.' 'This is my expression!" said Byron. 'Oh really!' I said; and then I made him as I wanted to, and when I was finished everyone said that it was a good likeness. When Byron saw it, however, he said, 'That is not at all like me - I look much more unhappy!' Ah, he always had to look unhappy!"
In the event, Thorvaldsen created more than one marble Byron, including not only the senatorial and mildly visionary head that so displeased the poet, but also the memorial statue in Trinity College, Cambridge - which conveys, if not exactly unhappiness, then at least something approaching the noble, reflective melancholy of Childe Harold. The writer has a foot on a ruined column, in allusion to his support for the Greek wars of independence and his death, in pursuit of the same cause, on the shores of Missolonghi. He also has his pen to his chin, rather like a child straining to think of the next word, which adds a homely (and sentimental) quality to what would otherwise be an unmitigated image of The Author as Hero.
Byron by Thorvaldsen is a reminder of the days when almost everyone of consequence or pretensions to it, passing through Rome, felt obliged to have their portrait carved by this large, blond, phlegmatic Scandinavian expatriate. Thorvaldsen's reputation, in post-Napoleonic Rome, was more or less unassailable. There were those, including Stendhal, who muttered that his statues tended somewhat to inertness; others who said that he had plagiarised Canova unforgivably when he was a young man; but the commissions came in regardless and at the peak of his powers, in the 1820s, Thorvaldsen had five studios in Rome, the largest of them approximately the size of Paddington station, and an entire army of assistants working under him.
Thorvaldsen's portrait busts, many of which are to be found, generally overlooked, in English country houses - Chatsworth alone has 10 Thorvaldsens, including a Byron - constitute what Denys Sutton once called "a Who's Who of Roman international society" in the first third of the 19th century. The artist still remains the only Protestant sculptor ever to have been commissioned to furnish Saint Peter's with a papal monument (Pius VII's funerary memorial, an unpleasingly ponderous work of which he was, rightly, always a little ashamed). These days he is little known, and he would seem to be one of art history's classic cases of mistaken identity: an artist of limited gifts, raised to greater stature than he deserved by accidents of contemporary taste. Yet in Denmark, where they still love him, and where his work is beautifully and romantically displayed, Thorvaldsen continues - against all the odds, in this stubbornly unheroic, anti-classical age - to hold his high reputation.
Thorvaldsens Museum, in the centre of Copenhagen, alongside Frederiksholms Kanal, close to Christiansborg Parliament, is now the only place in the world where you can still sense the former pre-eminence of Denmark's most celebrated artist. It is a wonderful museum, a work of art in itself and a building characterised by an entirely unique combination of the grandiose and the quaint. Within the building, in the echoing halls and atriums devised in homage to Thorvaldsen's classical spirit by the architect MS Bindeboll, they strive to keep the flame of Thorvaldsen's memory alight. Here, in rooms of burnt sienna, cobalt blue and sunflower yellow, they preserve the memory of a moment in European art when it seemed that the great, classical subjects were indeed the only subjects for art. Here, in stone relief, Priam pleads pathetically with Achilles for Hector's body, Cupid revives the swooning Psyche, and a Jason who looks suspiciously like Michelangelo's David ponders, with calm, impassive self-satisfaction, his recent acquisition of the Golden Fleece.
There is something touching about the Danish nation's fidelity to a man who, had he been born French or Italian (or British), would certainly have been allowed to slide quietly into the oblivion of art historical footnote status. In Denmark, it seems no opportunity to remember Thorvaldsen's former pre-eminence goes unmissed. Next year, which sees the bicentenary of the sculptor's so-called "Roman birthday" - 8 March, 1797, the day when Thorvaldsen first entered the Eternal City and, as he said, "the ice melted" from his eyes - will be marked with due solemnity. In 1998, yet larger celebrations will mark the 150th anniversary of the opening of Thorvaldsens Museum. This year, when Copenhagen is the European Union's designated City of Culture, they have been getting in some practice, with talks, lectures and frequent performances of a chamber opera based on the sculptor's uneasy relationships with women and connoisseurs. The opera is musically unexceptional and may, to non-Danish speakers, seem a little boring. But it has been exceptionally well attended by large and good- humoured crowds of Danes who are still, evidently, happy to consider Thorvaldsen as a national institution.
There is something of a paradox here. Thorvaldsen, after all, was a Danish artist who spent almost all his creative life abroad, and whose aesthetic rested precisely on the rejection of Denmark and the embrace of Italy. But nations take artists to their hearts for many and often somewhat peculiar reasons and Thorvaldsen is clearly a prime case of the phenomenon.
He was blessed by historical circumstance and shrewd enough to recognise the fact. The outside of Thorvaldsens Museum boasts a painted frieze depicting the artist's triumphant return to Denmark with all his works. Here we see delegations of politician and bureaucrat kneeling gratefully before the conquering hero on the Copenhagen quayside. Thorvaldsen, the master of a neo-classical sculpture tradition that was itself on its last legs, had been canny enough to suspect that coming home was his only chance of immortality. He did so, following many entreaties and on the sole condition that a museum be built to him and all his works, which he consented to leave to the nation. The museum was opened, some years after his death, in 1848, a year of bloody revolutions in Europe but one of bloodless constitutional reform in Denmark - it was the year that quietly sealed the Danish nation's rejection of monarchical absolutism and its embrace of democracy (when the delegation from the Danish Parliament finally went to King Ferdinand VII to demand reform, early one morning, he is said to have muttered, "So, at last they have come - tell them yes, of course they may have reform", and to have gone straight back to sleep). The nascent democracy naturally sought cultural symbols of its new-found sense of identity - and Thorvaldsen's gentle, bloodless, classical, implicitly republican art was perfectly adapted to the purpose.
These days, Thorvaldsen's classicism tends to look a little less classically perfect than it did 150 years ago. The men and women whom he immortalised in bust form look less like togaed Romans or vestal virginsand now are betrayed by their coiffures as distinctly 19th-century creatures. The passage of time has also revealed Thorvaldsen's own eccentricities and peculiarities. He seems a very various artist. Thorvaldsen, like so many painters and sculptors coming to Italy from dour, northern European Protestant countries, found moral and sexual release in Rome. There is an intensely powerful erotic charge to many of his smaller, more urgently and actively worked groups and figures (rumour has it that many explicitly erotic works of art were destroyed earlier this century by an unhappily prurient director of Thorvaldsens Museum). Thorvaldsen's most ambitious classical art attempts, in general with success, to suppress this and to replace Eros with moral and physical idealism. The result is faintly reminiscent, not in form but in spirit, of late Pre-Raphaelite painting. His figures are almost always drowsily static, heavy-limbed, as if drugged by their own, burdensome perfection. His young men and women embrace or part with curious, subtle dreaminess, as if to declare that the imaginary classical past that they inhabit is itself a dreamy fiction.
Thorvaldsens Museum was one of the very first museums in Europe to be devoted to the works of a single artist. News of its foundation may well have influenced JMW Turner, hardening his determination to leave his own works to the British nation in the hope (much more optimistic, and much more tardily realised) that a museum would likewise be built to his and his art's memory. The aim of Thorvaldsens Museum, however, was not simply to canonise Thorvaldsen but to depersonalise him - to turn the oeuvre of a single individual into a lexicon of ideal types of human being and behaviour. It was planned as a morally and physically improving capsule of perfection, a house of national emulation. This was to be "a new Parthenon"; and it was hoped that The People, who were to be encouraged at every opportunity to process through the museum's many rooms full of ideal men and women, gods and goddesses, would themselves be ennobled by some subtle process of aesthetic osmosis. The new Danes of the new Danish Republic were to model themselves on Thorvaldsen's classical ideal.
This type of civic idealism, with art as its focal point, is liable to seem almost comically alien to a late 20th-century Briton, reared in a culture of habitual cynicism, selfishness and social indifference. But in Denmark, where there is still a very strong, corporate sense that a nation is indeed a community, it still has a strong pull. When Thorvaldsen died, hundreds of Danes processed along with his funeral cortege, bearing torches aloft under the dim wintry sky of Copenhagen. The London Illustrated News carried an engraving of the event. The citizens of Copenhagen are still prepared to carry a torch for Thorvaldsen's art and the ideal of a noble, democratic society that it came to incarnate. There is something admirable about the Danes' determination to maintain Thorvaldsens Museum as a national institution.