For most of the 20th century the National Gallery in London kept Paul Delaroche's The Execution of Lady Jane Grey (1833) rolled up in its vaults, like a guilty secret. The painting had caused a sensation at the time of its initial exhibition in Paris in 1834, when it was sold to a Russian aristocrat for the highest price ever paid for a single work. Perhaps as a result, on seeing it in later years, the revolutionary poet Théophile Gautier delivered one of art history's more damning reviews: "I hated Paul Delaroche, whom I had never seen, with a savage and aesthetic hatred," he declared. "I could have eaten him, and thought him good eating, as the young Redskin thought the Bishop of Quebec."

Gautier's verdict, published when Delaroche was the starriest painter among Europe's nobility, stuck. Delaroche was a history painter when such painting was becoming history.

He was subsequently and universally characterised as a bourgeois dead end at the birth of the radical lineage of modernism that went from Delacroix through Manet to Cézanne and on to Picasso. "Delaroche was not born a painter," Gautier wrote. "He belonged to the middle classes. He tried to be interesting, which is a matter absolutely secondary in art."

Gautier then defined the terms in which art was thereafter to be judged. "If a visitor in a gallery stops before a picture, and instead of looking at it and enjoying it, first turns over his catalogue to find out what is the historical scene or anecdote represented, you may affirm of him, without fear of being mistaken, that unquestionably the man does not love painting. Delaroche has far too many such visitors."

With this verdict still in mind, therefore, it was with some trepidation and a warning from its then keeper of paintings, Cecil Gould, that the National Gallery finally brought the painting out of storage and put it on display in 1975. "The aim," Gould suggested, "is not to rehabilitate Delaroche. The only question concerning him which is likely to interest the current generation is why he was so successful in his lifetime."

Unfortunately for Gould, Delaroche's painting once again attracted too many visitors of what might still, in 1975, have been thought the wrong sort. The Execution of Lady Jane Grey - showing the teenage queen blindfolded and groping for the block on which she was to be beheaded - almost immediately became the most popular postcard in the National Gallery shop. The flooring in front of the painting was apparently the most scuffed and worn in the gallery; the "current generation", like those that had gone before, was not about to be told what it should like and what it shouldn't.
It says something for the stubbornness of popular opinion, or for the growing democracy of taste, that 35 years on, Delaroche's artwork is the theatrically lit centrepiece of an exhibition that may not quite be attempting a full-scale re-evaluation of the history painter, but which has certainly given up on sneering. The punters have prevailed. As the gallery's programme of events around the exhibition tacitly acknowledges, however - and as Gautier and the rest always feared - it is not the painter himself who is pulling in the crowds, so much as the melodramatic subject matter he depicts.

Delaroche's painting has become an occasion, following on from the 500th anniversary of Henry VIII's coronation last year, for yet more of what is becoming our favourite cultural pastime: Tudorphilia. Like Delaroche's image, what was long a guilty secret is now an open obsession. As kings-and-queens history is being squeezed from school timetables, our favourite century (the 16th) is enjoying success, not only in bestseller lists and box-office ratings, but also in critical approbation. David Starkey has never had it so good.

Accompanied by inevitable screenings of The Private Life of Henry VIII and Elizabeth as well as lectures on the "nine days' queen", Delaroche's painting feeds an appetite that takes in, on the one hand, the US Showtime/BBC soap The Tudors (now in its fourth season: "Henry's tumultuous relationships with his last two wives, Katherine Howard and Catherine Parr, and his final descent into madness . . .") and, on the other, Hilary Mantel's mesmerising Booker-winning novel, Wolf Hall, told through the life of Thomas Cromwell. Delaroche, you might say, succeeds in condensing all of that Tudorbethan intrigue into one startling image: young, virginal queen goes unseeing to her fate, accompanied by man in red tights caressing large axe.

As a tragic heroine, Lady Jane Grey, executed when only 17, comes second among Tudorphiliacs only to Anne Boleyn. There have been, at Amazon's last count, 19 biographies, novelisations or studies of the life of Henry's six-fingered second wife published in the past three years alone; Grey boasts a mere half-dozen. This recent wave of Tudormania, set in motion by the industrious novelist Philippa Gregory - with The Other Boleyn Girl - is fuelled now not only by a slew of Tudor stories, but also the many Tudor chat rooms on the internet, which discuss everything from the latest Boleyn reference on the American teen TV series Gossip Girl to forum threads devoted to whether or not Parr was the ideal stepmother.
The appeal is not confined to the Home Counties. Helen Lin, who lives in Boston, Massachussetts and who runs a website called Tudortastic (Why? "Because they are Tudor-fuckin-tastic"), explains some of the appeal. "I started being obsessed with Tudor history after the movie Elizabeth with Cate Blanchett came out," she tells me by email, "and even though now I dislike the movie immensely, it did start my fascination." She believes the period appeals to everyone because "it's got the tyranny of Henry VIII for the men, and the romance of Henry VIII for women". Best of all, it feeds the contemporary addiction to gossip, which, back then, was often a fatal activity; Heat would not have known where to start at the Tudor court. As Mantel suggests, "even the most fevered of bodice-ripping novelists has trouble keeping up with what these people said and thought about each other". It doesn't stop them trying, however.

Mantel herself was drawn to the period "because all the stories you ever wanted to tell are there behind the arras". Wolf Hall has a philosophy at its heart that Delaroche and his tradition of history painters would have understood very well. "Forget the coronations, the conclaves of cardinals, the pomp and processions," Mantel writes. "This is how the world changes: a counter pushed across a table, a pen stroke that alters the force of a phrase, a woman's sigh as she passes and leaves on the air a trail of orange flower or rose water; her hand pulling close the bed curtain, the discreet sigh of flesh against flesh." As those non-lovers of painting who buy postcards of The Execution of Lady Jane Grey would no doubt attest, you can read all this and more in the particular silk of the doomed queen's gown. Or at least you can convince yourself that you can.

If we believe that each age looks to a historical period to help it understand itself, what does the Tudor obsession say about us? No doubt the narratives catch some of our self-absorption (the insistent "I" of Thomas Wyatt's poetry sounds like the first truly modern voice), but also our interest in red-in-tooth-and-claw models of interaction. There was certainly no such thing as society in the brutal machinations of the Tudor court.
There are other echoes, too. England in the time of Henry VIII was isolated in Europe, its currency devalued, its exchequer emptied, and was ruled by bickering ministers who never said what they meant (Starkey recently described Thomas Cromwell as "Alastair Campbell with an axe"). It was - as Geoffrey Elton drummed into successive generations of Cambridge students - out of these conditions that the modern British state was first forged. Perhaps the answer to our Tudorphilia is simple: every organism has a need to understand its own DNA.

Tim Adams is the New Statesman's art critic.
“Painting History: Delaroche and Lady Jane Grey" is at the National Gallery, London WC2, until 23 May.

Paul Delaroche: the CV

1797 Born in Paris to a wealthy family
1816 Enters the École des Beaux-Arts at his father's instigation. Studies under Louis-Étienne Watelet
1822 Exhibits Josabeth Saving Joas at the Paris Salon and impresses Géricault, who, along with Delacroix, he later befriends
1830 After the July Revolution, his notoriety grows; he is commissioned to paint a large work called The Storming of the Bastille
1833 Paints The Execution of Lady Jane Grey
1856 Dies in Paris
1857 Prompted by a retrospective exhibition of Delaroche's work, Théophile Gautier condemns his paintings for relying heavily on historical context

Benjamin Mullen