By 15 July, Lefine had been able to draw up a preliminary list of a dozen or so names. It included two that Margont would have preferred not to see: Colonel Pégot, who was in charge of the 84th of the Line, and Colonel Delarse, one of General Huard’s aides-de-camp. Delarse commanded the 1st Brigade of the Delzons Division, which included the 84th, together with the 8th Regiment of Light Infantry and the 1st Croat Regiment.

Lefine and his men had then begun to reconstruct the movements of the suspects on the night of the murder. The fact that Margont had always been exasperated by the question of shoes in the French army had given him an idea. One of a French soldier’s best weapons was indeed his shoes. The imperial troops were second to none in their ability to cover long distances in record time. Napoleon had brilliantly incorporated this advantage of speed into his strategic calculations when launching his infantrymen on frenzied, crazed, hellish marches. As a result, in 1805, on the way to Austerlitz, Margont had seen soldiers literally die of exhaustion. Others fell into such a deep sleep that the officers could not wake them, even by prodding them with the points of their sabres. They had nevertheless continued to advance with the result that, thanks to some skilful manoeuvres, Napoleon had succeeded in preventing the Austrian army of General Mack from linking up with the bulk of his forces. The Austrian army had finally been encircled in the city of Ulm. The Austrians had lost twenty-five thousand men, whom they sorely missed a few days later during the battle of Austerlitz …

Yet, despite the obvious importance of mobility for the regiments, the shoes used by the Grande Armée were very badly designed. There was no difference between right or left: the soldiers’ feet shaped the shoes during the march. There were only three sizes: small, medium and large, so it was hard for feet of other lengths. The shoes were supposed to last for five hundred miles, but many of the suppliers swindled the army and often, if you set off from Paris with new shoes, you ended up in Brussels barefoot.

Margont had decided to take advantage of this paradox. He had suggested that Jean-Quenin should write a letter asking the regimental cobblers to answer a list of questions. The medical officer claimed he wanted to do some research into the shoes in order to rethink their design. Lefine met the cobblers, read them the letter and immediately drowned them in a sea of words. He talked on and on. Sometimes his slick talk endeared him to them and he obtained all the information he wanted; other times he infuriated them and people said all they knew just to get rid of this wretched sergeant. Casually slipped in among the questions was one about the shoe sizes of the senior officers …

But this painstaking task proved to be unbearably slow.

The complete translation of the private diary had taught Margont nothing new. Maria Dorlovna suffered from loneliness. Being of a sensitive and dreamy disposition, she fed her hopes by reading romantic literature. Her writing was steeped in poetic melancholy, a feature that was all the more remarkable given that few women of her class had the opportunity to learn to read and write. She had believed that a miracle was possible. What had her murderer done to seduce her so quickly? What, then, could a Prince Charming possibly be like?

July 21 started badly for Margont as that morning bore an annoying resemblance to the preceding ones. How ironic to be constantly singing the praises of freedom and yet to be himself a prisoner! Where was the freedom to go where you liked? He had to continue advancing in this cloud of dust that the road to Moscow had turned into. Where was freedom of speech? Tiredness often made it impossible to talk. The laborious progress of the Grande Armée reminded Margont of his years spent in the abbey of Saint-Guilhem-le-Désert. The old stone walls had been replaced by vast plains. Certain moments from his life there came back to him as if linked to the present by a common thread of hopelessness. He pictured himself again scraping away night after night at a stone hidden under the bed of his monastic cell. He had never succeeded in dislodging it. He remembered the obdurate expression of certain monks when he pleaded with them to let him accompany them on visits outside the monastery.

As a child his mind had been an empty vessel in an empty, locked room. Then he had discovered books and had feasted on words, dreams and the promise of travel. But even today he still retained this searing memory of emptiness. He still needed to fill himself up: with food, with any kind of learning, with reading … So he had devised all sorts of strategies for warding off boredom, this nothingness that threatened to swallow him up. He had learnt the rudiments of Russian; recited to himself entire monologues from plays, throwing himself into the roles; written articles for the newspaper he wanted to launch; scribbled notes and sketches in a notebook in the hope of having his memoirs published … And, to that end, he said to himself, in order to give an accurate idea of this long march in a work about the Russian campaign, he would have to leave dozens of pages blank. He had read all the books he had been able to bring with him: Candide, Hamlet, Macbeth, a treatise on ants – creatures whose ingenuity and tenacity fascinated him – and accounts of travels in Russia. He had been compelled to lighten his load by leaving these works by the wayside, hoping that they would be picked up by someone else. No soldier in his company had wanted them. Many of them could not read, and in any case with a kitbag containing three shirts, three pairs of socks, three pairs of gaiters, two pairs of trousers, dress uniform and the regulation ten kilos of rations … He frequently listened to the soldiers recounting their life stories, whilst being careful not to tell his own. Lastly, like the other captains, he spent a ridiculous amount of time trying to maintain order.

The columns of soldiers were becoming more and more ragged, the ranks slacker and slacker. Exhausted stragglers, left behind by their regiments, attracted the attention of sergeants, who gesticulated at them, but to no avail. Some collapsed, overcome by sleep as if hit by a thunderbolt. Others lengthened their stride to regain their position before falling behind once more. Sometimes the officers turned a blind eye, but those in command could also prove ruthless. A flurry of punishments would then be meted out and surreal scenes would ensue: here three infantrymen being forced to wear their uniforms back to front as a mark of dishonour; there a straggler running back and forth between two columns of soldiers ten times without stopping; yet another miscreant being put on guard duty every night. There seemed no limit to the inventiveness of the punishments.

Fortunately, the men were united by a feeling of camaraderie. When a young recruit threatened to fall by the wayside, one veteran carried his musket and another his kit. When some of the men could no longer keep up, the regiment imperceptibly slowed its pace, or lieutenants would be furious to witness a sudden general outbreak of blisters and corns. Resupply problems had become so severe that officers sent detachments out looting to bring back what they could, which in most cases meant little or nothing. Everyone always volunteered for this sort of mission, despite the considerable risks posed by the Cossacks.

Originally, the Cossacks were free peasants and soldiers who fought the Russians, the Poles or the Tartars but now they were subjugated by Russia. Enamoured of nature and freedom, always on horseback, armed with lances and fanatically devoted to the Tsar, these marvellous horsemen were key elements in the Russian army. Highly mobile, swift and unobtrusive, they attacked isolated groups and concealed Alexander’s troop movements by disrupting reconnaissance expeditions and making it impossible to estimate their number by their constant comings and goings. At the head of the Cossacks of the Don was Hetman Platov, who had sworn to bring Napoleon back to St Petersburg in chains.