On the 23rd of March the Allied sovereigns, including that of the United Kingdom, signed, by their plenipotentiaries, a new treaty of alliance offensive and defensive, on the same principles as the Treaty of Chaumont, entered into in March, 1814. The Duke of Wellington then hastened away to Belgium to muster his forces there—for Belgium, as it had been so often before, was sure to become the battle-ground on this occasion. So early as the 5th of April he announced that he had placed thirteen thousand four hundred men in the fortresses of Belgium, and had besides twenty-three thousand British and Hanoverian troops, twenty thousand Dutch and Belgian, and sixty pieces of artillery. Unfortunately, the bulk of his victorious army of the Peninsula had been sent to the inglorious contest with America, where a good naval blockade would have been the most effectual kind of warfare. But he observed that Buonaparte would require some time to assemble a strong force, and this time must be employed by Britain to collect a correspondingly powerful army. The Duke, with accustomed energy, not only applied himself with all his strength to this object, but to stimulating, by letters, the Allied sovereigns to hasten up their quotas, some of them notoriously the slowest nations in the world.
Buonaparte landed at Cannes on the 1st of March. His advanced guard presented themselves before Antibes, and were made prisoners by the garrison. This did not discourage Buonaparte; he advanced by forced marches with his now less than one thousand men, and leaving behind him his train of artillery. Till he reached Dauphiné, however, he received very little encouragement from any party. All the authorities, proprietors, and clergy, stood aloof; only a few peasantry occasionally cried "Vive l'Empereur!" but did not join him. He began to be very uneasy. But on the 7th of March, as he approached Grenoble, Colonel Labédoyère, who had been gained over before, came out with an eagle in his hand, and at the gates distributed tricolour cockades, which had been concealed in a drum. Buonaparte advanced alone towards the troops, and called on any one who wished to kill his Emperor to do his pleasure. All cried "Vive l'Empereur!" and crowded round him. General Marchand endeavoured to recall the soldiers to their duty, but in vain.
Whilst Napoleon was thus advancing towards Paris, the besotted Bourbons rather rejoiced in it, for they said it would compel the two chambers to invest the king with despotic power—that was what they were still longing for; and Louis himself, addressing the foreign ambassadors, bade them assure their sovereigns that he was well, and that the foolish enterprise of "that man" should as little disturb Europe as it had disturbed him.
Monsieur and the Duke of Orleans hastened to Lyons, and the Duke of Angoulême to Nìmes. Corps of volunteers were called out, and an address to the people was composed by Benjamin Constant, calling on them to defend their liberties against Buonaparte; and a woman on the staircase of the Tuileries exclaimed, "If Louis has not men enough to fight, let him call out the widows and childless mothers who have been rendered such by Napoleon!" Meanwhile the conspiracy of General l'Allemand and his brother at Lille, to carry over the garrison of eight thousand men to Napoleon, was discovered by General Mortier, and defeated. Had this plot succeeded, Louis and his family must have been made prisoners. But that was the extent of the adhesion to the Bourbon cause.
When Buonaparte reached Lyons, the soldiers, in spite of the Duke of Orleans, of Monsieur, and of Marshal Macdonald, went over to him to a man. He was now at the head of seven thousand men, and Mâcon, Châlons, Dijon, and nearly all Burgundy declared for him. Marseilles and Provence stood out, the authorities of Marseilles setting a price upon his head. But being now in Lyons, Buonaparte issued, with amazing rapidity, no fewer than eight decrees, abolishing every change made by the Bourbons during his absence, confiscating the property of every Emigrant who had not lost it before, restoring the tricolour flag and cockade, and the legion of honour; abolishing the two chambers, and calling a Champ-de-Mai, to be held in the month of May to determine on a new constitution, and to assist at the coronation of the Empress and the King of Rome. He boldly announced that the Empress was coming; that Austria, Russia, and Great Britain were all his friends, and that without this he could not have escaped. These decrees, disseminated on all sides, had a wonderful effect on the people, and he advanced rapidly, reaching Auxerre on the 17th of March. He rode on several hours in advance of his army, without Guards, talking familiarly with the people, sympathising in their distresses, and promising all sorts of redresses. The lancers of Auxerre and Montereau trampled the white cockade under foot and joined him. He appointed Cambacérès minister of justice; Fouché, of police; and Davoust Minister of War. But Fouché, doubting the sincerity of Buonaparte, at once offered his services to Louis, and promised, on being admitted to a private interview, to point out to the king a certain means of extinguishing the usurper. This was presumed to mean assassination by some of his secret agents, and was honourably rejected by Louis, and an officer was sent to arrest Fouché; but that adroit sycophant retired by a back door, locking it after him, got over a wall, and was the next moment in the house of the Duchess of St. Leu, and in the midst of the assembled Buonapartists, who received him with exultation.
Thus surrounded by treason, Louis doubted the fidelity of Soult, who resigned his command; but he trusted Ney, and sent him to attack Buonaparte in the rear, whilst an army at Mélun, under Clarke, Duke of Feltre, was to attack him in front. Ney took leave of Louis on the 9th of March, declaring that he would bring Buonaparte to him in a cage; but at Lons-le-Saulnier, on the 14th, he received a letter from Napoleon, calling him "the bravest of the brave," and inviting him to resume his place in his army, and Ney went over at once. To abate the public opinion of his treason, he pretended that this expedition had been long arranged between himself and Buonaparte, but this Buonaparte at St. Helena denied.
Astounded by these repeated defections, Louis tried to gather some notion of the state of other bodies and troops about him. He attended a sitting of the Chamber of Deputies, and was received with acclamation; he reviewed twenty-five thousand of the National Guard, and there was the same display of loyalty; he inspected six thousand troops of the line, but there the reception was not encouraging. He finally summoned a council at the Tuileries, and there the generals declared frankly that he had no real means of resisting Buonaparte. This was on the 18th of March, and Louis felt that it was time for him to be making his retreat. At one o'clock in the morning of the 20th he was on his way towards Lille, escorted by a body of Household Troops. It was time, for that very day Buonaparte reached the camp of Mélun, where Macdonald had drawn up the troops to attack him; but Buonaparte threw himself amongst them, attended only by a slight escort of horse, and the soldiers all went over to him with a shout. Macdonald rode back to Paris, and, following the king, assumed the command of the Guard accompanying him. Louis hoped that the troops at Lille, under Mortier, would stand by him; but Mortier assured him of the contrary, and so, taking leave of Macdonald on the frontiers, Louis pursued his way to Ostend and thence to Ghent, where he established his Court. The Household Troops who had accompanied him were disbanded on the frontiers, and in attempting to regain their homes by different routes, most of them were killed, or plundered and abused.
On the evening of the very day that Louis quitted Paris Buonaparte arrived in it. He had slept on the night of the 19th at Fontainebleau, where, in the preceding April, he had signed his abdication. No sooner had the king departed than the Buonapartists, who were all ready for that event, came forth from their hiding-places. Lavalette resumed his position at the post-office, and thus managed to intercept the proclamations of Louis, and to circulate those of Buonaparte. Exelmans took down the white flag from the Tuileries and hoisted the tricolour, and a host of the adherents of the old Imperial Government, hurrying from all quarters, thronged the avenues to the palace, and filled the court of the Carrousel. There were ex-Ministers of Buonaparte, ex-councillors, ex-chamberlains, in imperial costume—in short, every species of officers and courtiers, down to cooks, and butlers, and valets, all crushing forward to re-occupy their places.
The Guards at the gates stood with tricolour cockades on their hats, and the great ladies of the Court came driving in, for they were not far off. The Duchess of St. Leu had been permitted to remain in Paris, and her house had been the focus of all the Buonapartist adherents and conspiracies. From that centre had been sent summonses to every branch of the Buonaparte family to be in readiness, and all had responded except Cardinal Fesch, Louis Buonaparte, and Eugene Beauharnais, who had too much sense to quit Munich with his wife, the daughter of the Bavarian king. Even Murat, to his ruin, had been induced to declare for Buonaparte once more.
When the returned Emperor, therefore, drove up to the Tuileries, at nearly ten o'clock on the night of the 20th—a foggy and wet night—his carriage, covered with mud, was surrounded by his friends, as if he had only been absent on one of his campaigns. As he stepped out of his carriage in his old grey great-coat and cocked hat, now to be seen in the museum of the Louvre, he was instantly so hemmed in that he called out, "My friends, you stifle me!" and a number of general officers at once hoisted him upon their shoulders, and thus bore him into the palace and up into the State apartments amid deafening shouts of "Vive l'Empereur!"