I first started going to France almost 50 years ago, on motoring holidays with my parents and brother. The towns and villages we then visited - quaintly, they were still filled with no one but the French - had a solid, unchanging feel to them; also, a familiar morphology: from smart mairie and post office to dilapidated lavoir and rank pissoir, from war memorial listing unforgotten dead to blank walls pasted with the huge words "DEFENSE D'AFFICHER - LOI DU 29 JUILLET 1881" (a proclamation far more strident than the flyers it was designed to deter). Behind this ordinary, diurnal France, giving it wider and deeper meaning, was the monumental France to which my schoolteacher parents introduced me (at times, inflicted upon me): the chateaux and churches, museums and public buildings, art-works and ruins - a France of history, power and money, of official, architectural beauty. There seemed an extraordinary amount of it around, its symbols leaping out from every fold of the yellow Michelin map. A back-seat navigator, I would warn my parents of what lay round the next bend. A solid black oblong denoted a chateau worth slowing down for; a similar oblong with legs at each corner one worth a stop; a triangle of black dots meant a ruined castle; while a curious mark, like a wonky version of the pi symbol, indicated some prehistoric vestige. All this seemed just as solid and eternal as the daily life, if not more so.
When we toured the chateaux of the Loire, I couldn't help noticing that many of these great palaces seemed remarkably empty of furniture, and was given to understand that it had all disappeared in the revolution. Into my mind came vague images - perhaps culled from the film of A Tale of Two Cities - of looting sans-culottes with wild eyes and bad shaves. The green Michelin guidebooks to which we referred for our facts were, I now realise, written and edited by a team diplomatically keen not to offend any strand of French opinion; so there was much elision, and a tactical unwillingness to take any controversial (or even discernible) side in France's long, internecine history. Nor did the books indicate how precarious had been the earlier life of this solid monumentality we dutifully visited. Still less did they mention, let alone salute, the man without whose decisive influence and actions what the French now call their patrimony would have been considerably diminished: Prosper Mérimée.
On this side of the channel, Mérimée (1803-1870) is mainly remembered as the author of the novella from which Carmen was drawn: though Bizet's opera, in the words of Mérimée's best British biographer, Alan Raitt, is "no more than an emasculated and prettified version of Mérimée's tale". He wrote fiction - specialising in themes of cruelty, revenge and the implacable woman - plays and poetry. He was a serious Anglophile, who once proposed marriage to Mary Shelley, and was so well known at the British Museum that the guards used to salute him when he arrived; he was also passionate about Spain, and in later life a Russophile who translated Pushkin, Turgenev and Gogol. He was a traveller, a courtier, an Academician, friend of Stendhal, lover of George Sand, truffler of the sexual low-life, and a senator under Napoleon III. But his true, if largely forgotten, claim to enduring fame is as the second Inspector General of Historic Monuments, a post he occupied from 1834 to 1860.
There had been previous attempts to catalogue and protect France's architectural history, most of them either compromised or half-hearted. If the French revolution had been at times revengefully destructive, it also introduced for the first time the idea of officially conserving works of art and architecture. So each decree of confiscation also included a demand for protection: these buildings, these paintings, these tapestries were now in the care of the people. Between 1790 and 1795 there was a Commission of Monuments, set up to make an inventory, with the help of regional correspondents, of all that was worth preserving. Although what was worth preserving above all was the revolution itself, and when it came under attack from counter-revolutionaries and foreign armies, there was much patriotic handing in of silver, gold, rich cloth, vases and so on. Bronze statuary was melted down, while the lead roof of Chartres cathedral was stripped off in Year III on the grounds that "our prime concern is to crush our enemies". The commission hoped to protect the royal tombs at Saint-Denis - "not out of love for them, but for the sake of history and the philosophic idea". But the Convention, intent upon expunging the very idea of monarchy, authorised the destruction of "these monuments to pride and flattery". Since what later becomes a nation's patrimony (and its list of tourist attractions) normally starts off as just such vainglorious display, it is fortunate this principle was not more widely applied.
Kings nevertheless returned to France, and it was with the bourgeois monarchy of Louis-Philippe, brought in by the "Three Glorious Days" of July 1830, that the protection of the nation's patrimony became an urgent matter, supported at the highest levels. Ludovic Vitet, appointed the first Inspector General of Historic Monuments, defined his task as to make an inventory of all buildings which "because of their date, their architecture, or the events to which they have borne witness, merit the attention of the archaeologist, the artist, and the historian." Such listing was clearly a massive task: Mérimée drily observed that it would probably take 250 years and require 900 volumes of illustration to go with the text. But it was also a thrilling, generous idea - "administrative romanticism", in one expert's nice phrase - typical of the new generation which came into power in 1830. The great 19th-century critic Sainte-Beuve later wrote: "It was like a kind of pilgrimage. Experts combed the provinces, rushing towards any town which had a steeple pointing like a finger into the sky, towards every church tower and Gothic arch. They hunted through the oldest parts of towns, explored the narrowest alleyways, and stopped dead at any piece of incised or decorated stonework."
This surge of enthusiasm came from several sources. First, a panicky realisation that parts of France were just being demolished, carted away, broken up. The principled (or vindictive) hostility of revolutionaries to the property of aristocracy and church had given way to pragmatic recycling by builders treating ancient monuments as quarries, and antiquarians rounding up loot to sell abroad. In April 1819 the Minister of the Interior had asked Prefects to report on the most important buildings in their départements "in order to prevent them being dismantled and taken away by the English". Victor Hugo declared "Guerre aux demolisseurs!" (War on the vandals) - and wrote in 1825: "There are two things about a historic building: its use and its beauty. Its use is a matter for its owner, but its beauty belongs to everybody. So an owner goes beyond his rights in knocking it down." This was a less politicised - though still militant - version of the revolution's declaration of public ownership. Hugo gave further, fictional impetus to his campaign with the novel Notre-Dame de Paris (1831), in which the cathedral becomes as vivid a character as Quasimodo himself.
What the thieving English wanted was Gothic, being themselves in full Revival mode. The French came later to the rediscovery of Gothic, but with a fuller national purpose. Gothic was the authentic architecture of France, whereas Classicism was a foreign interpolation. Viollet-le-Duc, who began as Mérimée's protégé, and later became the most famous architect and restorer in 19th-century France, wrote that "Our country is closer to medieval France than to classical Rome. Our religion and our climate have remained the same. The building materials have also remained the same, and we would feel more at home in a 13th-century French mansion than in any palace of Lucullus." Gothic was patriotic; Gothic also best expressed the Catholicism which was now back in fashion.
But there was also a political aspect to the new regime's enthusiasm for ancient monuments. The July Monarchy had no real legitimacy, so it needed to confect one. In rebranding the country it therefore claimed to represent both new and old: to draw on France's recent revolutionary heritage, but also to annex the idea of ancient France, now being rediscovered and properly valued. Though there was a potential problem here: if you identified your new regime with a collection of collapsed and collapsing edifices, what sort of a message was that sending out? So the concept of not just protection but restoration was vital. The rediscovered heritage was to be presented once again as the restorer knew - or guessed, or hoped - it originally had been. In the old days, if there was a broken 12th-century capital in a church, it would have been replaced with a capital of the 13th, 14th or 15th century, depending on when such replacement happened. Now, in the second quarter of the 19th century, the notion of re-imagining, and then attempting to transport, a building back to its original state was for the first time introduced on a wide scale. This was not to prove a simple matter.
Mérimée was still only 30 when appointed to succeed Vitet on May 17 1834. He had a broad general grounding in the arts (his father was perpetual secretary at the Ecole des Beaux-Arts, his mother an accomplished portrait painter), but knew he was inexperienced in archaeology. Alexandre Dumas commented sardonically that Mérimée would have to begin by learning what he would then be expected to teach others. But he did learn, and quickly. On appointment, he told his English friend Sutton Sharpe that "the job fits my tastes and temperament perfectly: it appeals to both my idleness and my love of travel". But there was little idleness about the new Inspector General. Only six weeks into the job, he set off for the south of France on what was the first of a series of annual tours of inspection. Each summer for the next 18 years, he would criss-cross the country for weeks and months, examining and reporting, chivvying and condemning. The roads were bad, the coaches uncomfortable, the inns bug-ridden, the food often inedible, the women (and Mérimée was very keen on women) often implacably virtuous, and the local experts at times dunce-like. Mérimée's private letters are full of steam being let off: "The truth is that the life I lead is absolutely exhausting. When I'm not travelling around by coach, I get up at nine, have breakfast, then give audience to librarians, archivists and the like. They take me to look at their wretched ruins, and if I say they aren't Carlovingian, they look on me as a blackguard and start intriguing with the local deputy to get my salary reduced. Caught between conscience and self-interest, I tell them their monument is marvellous and that there's nothing in the north to compare with it. Then they invite me to dinner, and the local paper says I'm the devil of a clever fellow. They beg me to inscribe a sublime thought in an album; I obey with a shudder. At the end of the evening, they ceremoniously escort me back to my hotel, which prevents me from indulging in vice. I go back to my room worn out and sit up putting together notes, drawings, official letters, etc. I wish those who envy me could see me then."
Mérimée certainly found some of the local antiquaries comically cocky - liking to classify things as "Phoenician" when in doubt - and some of the architects profoundly ignorant: the man at Béziers was "the biggest ass ever to hold a drawing-pen", the one at Saint-Savin "a man quite without education and remarkably stupid". Some of the provincial officials were obstructive, and some of the clergy proprietorial: the curé at Chauvigny, Mérimée noted with astonishment, insisted "that the church belonged to him". But the Inspector General would have made little headway if he had been heavy-handed, or bossily Parisian. He was not just extraordinarily industrious, knowledgeable and incorruptible; he was also charming and persuasive. Viollet-le-Duc, who travelled with him on several of his tours, wrote: "Without even noticing what was happening, the person to whom he was speaking was induced to give him all the information he wanted, and confess everything to him. He would have made the most amiable examining magistrate one could imagine. At the same time, he was a good diplomat and a clever politician."
He had to be; not least because he and his commission had little more than moral authority. The fact of listing a monument (1,076 were put on the roll in 1840; nearly 4,000 by 1849) did not give it any legal protection. If an owner knocked a building down, or a municipality decided on a piece of street-widening to the detriment of some awkward medieval vestige, there was nothing Paris could do about it: the necessary protective laws were not finally introduced until 1887-89, nearly two decades after Mérimée's death. So his role was part aesthetic expert, part moral presence, part patriotic cheerleader. When Guizot, the Interior Minister, described the job of Inspector General in 1830, he not only drew its terms very widely (museums, private collections and manuscripts were included as well as buildings and works of art) but announced the hortatory principle which was to infuse it. The task of an inspector general, he wrote, was to "stimulate the zeal" of local authorities, "so that no building of incontestable merit would be lost through either ignorance or collapse". This collaboration with departmental and municipal authorities was desirable for democratic reasons, and necessary for economic ones. Listing resulted in state funding only in one case in three: it was intended to stir local pride in the monument, local support, local money.
What Mérimée discovered, as he went on his annual rounds, was that much of France's monumental patrimony was in a state of near-collapse. The roof of Chartres cathedral was on the point of falling in; the wall-paintings at Saint-Savin - the largest array of medieval frescoes in France, and possibly Europe - had been crudely obliterated with whitewash; a few days after Mérimée had inspected the Vice-Regent's tower, "one of the most ancient edifices in Avignon", it simply fell down. Symbolic of much elsewhere was the condition of the great abbey church at Vézelay. Its left-hand tower had been pulled down by Protestants in 1569; revolutionaries had hacked off offending bas-reliefs; and then, "as if to prove that the 19th century did not yield to the past in the matter of vandalism", the Army Corps of Engineers, engaged in mapping the country, had built "a ridiculous octagonal observatory" right on top of the remaining tower. Walls had fallen in, or were rotting away from damp; trees were growing out of the stonework; the vaulting could scarcely hold together any longer; and as Mérimée sat in the church sketching the grim scene, stones from the roof kept falling all around him. The town itself, with only a thousand inhabitants and no significant industry, didn't have money enough even to stabilise the church in its current moribund condition. "So things get worse by the day," Mérimée wrote in his report to the minister. "If we delay our support any longer, the church will become so dangerous that we shall have to pull it down."
Nor was it merely time and history that were assailing the patrimony. Theft, vandalism and self-interested urban development were happening by the week. The famous Roman mausoleum outside St Rémy may be 18m high; but shortly before Mérimée inspected it in October 1834, "an Englishman" (if in doubt blame les Rosbifs) managed to scale it in the middle of the night and make off with the heads of the two draped figures from the very top. In Avignon, Corsican soldiers billetted in the Palais des Papes supplemented their pay by chipping off the medieval frescoes and selling them; while a horticultural entrepreneur had taken over the city's famous bridge, planting almond trees and cabbages on it. In La Charité sur Loire, two locksmiths had built their houses against the wall of the abbey church, so that their sleeping alcoves were decorated with spectacular 11th and 12th century bas reliefs. A month before Mérimée's arrival, a soldier had lodged with one of the locksmiths and slept next to a sculpture of God the Father surrounded by saints and angels. He had a less than satisfactory night. In the morning he took his stick, chastised the figure of God with the words: "You invented bed-bugs, so this one is for you," and knocked its head off.
There was also institutional vandalism to contend with. Historic buildings were now being used as storehouses, shops, stables and beerhalls. The Palais des Papes was a barracks, Noirlac Abbey a china factory. Since the revolution, the church of Saint Etienne in Strasbourg had been used first as a music hall, later as a tobacco warehouse. Saint Savinien at Poitiers was a prison, and its choir a padded cell: the Inspector General was faced with a request to destroy the interior's few remaining sculptures of worth, to stop the inmates treating them as climbing stones and making their escape. Mérimée's task was rarely helped by other government bodies: he found the Ministry of Ecclestiastical Affairs obstructive, the Ministry of Works destructive, and the Ministry of War "the biggest vandal in France". Near Carnac, road-builders, unwilling to make a detour of a few metres, smashed "the beautiful menhirs of Erdeven" to powder. The city of Orléans pulled down its old Hotel-Dieu. At Bourges, the richly late-Gothic Maison de Jacques Coeur had been turned into a courtroom, a change of use which wrecked the internal layout and decoration. Mérimée judged it impossible to restore the interior to its original condition, because it would mean that "we would be obliged to invent". He was constantly faced with such decisions, and expressed his principles in the dictum: "It is better to consolidate than repair, better to repair than restore, better to restore than embellish, and in no circumstances knock down."
Yet worse than individual or institutional vandalism was something less immediately obvious, indeed paradoxical: the mutilations inflicted by wrong-headed restorers. Of all the enemies Mérimée faced, bad restoration was the one which obsessed and infuriated him most. "I have no hesitation in saying that neither the iconoclastic fury of protestantism nor the stupid vandalism of the revolution has left such deplorable marks on our monuments as the bad taste of the 18th and 19th centuries. The barbarians at least used to leave ruins; the so-called repairers have left us only their own sorry work." Medieval frescoes were whitewashed out; crude new oil painting made churches look like taverns; old stone was brutally scraped away, until it matched the colour of the new stone with which it had been patched. At Bayeux they installed proud new stained glass which was nothing but "a gaudy and pretentious pastiche". At Saint-Savin, one of the buildings closest to his heart, the Inspector General was reduced to fury by the enthusiastic repainting and filling-in of the frescoes: "the most revolting sight in the world", he called it. The colours were luridly modern; there was a grotesque portrait of God the Father "squinting horribly", plus an eagle of St John the Apostle looking more "like a cockerel". Within an hour Mérimée had this destructive restoration effaced.
It is amazing that, with so many enemies, he kept both his sanity and his stamina. "I am already at war with so many towns," he wrote in the 1840s, "that one more or less doesn't worry me much." Of course, given that the commission only had moral and persuasive authority, there were defeats and losses - some of which occurred after a building had supposedly been saved. The state might list a church, restore it at considerable expense, and hand it back, only for the community to finish the job according to its own taste: as the architectural historian Paul Leon put it in his magisterial La vie des monuments français, "Their barbarous ignorance often succeeded in removing from the edifice its entire value as a work of art." When Mérimée reported on Carpentras in September 1834, he described a delightfully walled and fortified town, like a junior version of Avignon. Despite his praise, when he returned 11 years later, the town had pulled down the better, southern ramparts, and was hard at work destroying the rest. "You wouldn't recognise the place," Mérimée wrote to Vitet. "It's now the filthiest and vilest dump you could imagine." Avignon similarly wanted to sacrifice its ramparts to facilitate the railway line, whose course would also have chopped through the famous old bridge - a piece of vandalism that was successfully resisted.
It's true that the school of architect-restorers brought into existence by Mérimée and his commission did not always follow his careful and properly austere precepts. At Blois the architect Duban, "seeking a public success", commissioned an equestrian statue of Louis XII, plus all sorts of balustrades, ornaments and window-framings - rank embellishments and inventions. Viollet-le-Duc - especially after 1860, when Mérimée's direct influence waned - increasingly produced fully reinvented medievalism: the brand-new old. Knowledgeable tourists of a later generation, such as Henry James (in 1882) and Edith Wharton (in 1908), loathed much of what he did. They much preferred evocative and crumbling old piles. As Wharton wrote: "How much more eloquently these tottering stones tell their story, how much deeper into the past they take us, than the dapper, weather-tight castles - Pierrefonds, Langeais, and the rest - on which the arch-restorer has worked his will, reducing them to mere museum specimens, archaeological toys, from which all the growths of time have been ruthlessly stripped!"
Mérimée was well aware of the dangers of reinventing the past, though he sometimes kept a diplomatic silence. Viollet-le-Duc had made his name by saving Vézelay and restoring Carcassonne in a way that pleased even Wharton; but increasingly he tended to rely on his own imagination. The chateau of Pierrefonds was given a "riotous treatment" by Viollet at the command of the Empress Eugénie, who later asked Mérimée what he thought of it. "It is a piece of work," he replied, "before which I feel utterly crushed." The empress, not reading the ambiguity, replied: "Thank you, you are a true friend."
In the 1840s, Mérimée wrote that "the job of an inspector of historic monuments is to be a voice crying in the wilderness"; but his voice resounded through that century and beyond. A French critic of the 1920s noted the paradoxical turn of his life. He had been "a young man who had put everything into trying to write like Voltaire and dress like Beau Brummell, yet who became the most diligent of bureaucrats and the most zealous of archaeologists". A further paradox was that this convinced atheist, who had not even been baptised, was responsible for saving large numbers of ecclesiastical buildings - first from falling down, and then from the bright decorative vandalism of know-nothing restorers and proprietorial clergy. Leon, summing up Mérimée's achievements, wrote that "Thanks to him the cathedrals of Laon and Vézelay and the Abbey of Saint-Savin are still standing, and towns such as Caen, Avignon, Cunault, Saulieu and Narbonne are still dressed in their finery of great monuments." Modern tourists, seeing a distant spire pointing to the heavens, spotting the glisten of pepper-pot towers half-lost in woodland, or gazing up at the ribbed vaulting of an airy abbey, should pause and give thanks to the man without whom one French town after another might have ended up looking like Carpentras.
And yes, I have been to Carpentras. All I can remember is the pizza I ate there.
· The Man Who Made France Old, two programmes about Prosper Mérimée presented by Julian Barnes and Hermione Lee, will be broadcast on Radio 4, July 12 and July 19