Tilsit followed, and Napoleon showered honours on his trusty lieutenants. On June 30, 1807, he gave to Lannes the principality of Sievers in the department of Kalish, and on March 19, 1808, he conferred on him a greater honour when he created him Duke of Montebello in memory of his famous victory.
The Duke of Montebello spent his days of peace for the most part at Lectourne. He was summoned thence in October, 1808, to accompany the Emperor to Erfurt, and there the Czar Alexander made a special hero of his old adversary of Austerlitz, Pultusk, and Friedland, and presented him with the grand cordon of the Order of St. Andrew.
The period between Tilsit and Erfurt gave Lannes the last peaceful days that he ever spent, for from Erfurt he was hurried off again to war, this time to Spain. As usual when there was hard fighting in prospect, Napoleon knew that he could ill afford to do without his most trusty and able lieutenant. But Lannes had but little enthusiasm for the Spanish War. His reputation stood so high that there was little chance of enhancing it, and by now the fire-eating republican soldier was settling down into a quiet country gentleman, who preferred the domestic circle and the pleasure of playing the grand seigneur before an audience of friends to the stir of the camp and the pomp of the court. But he was too well drilled in soldierly instincts to refuse to serve when summoned by his chief, and accordingly, much against his will, he set out on what he expected to be a short inglorious campaign of a couple of months against a disorganised provincial militia.
Lannes accompanied the Emperor on his journey to Spain, attached to the headquarter staff without any definite command, for the Emperor knew that all was not well with the armies there, but he could not, until he had himself looked into the question, decide where he could use to the best advantage the great administrative and tactical ability of the Duke of Montebello. During the hurried crossing of the mountains of Tolosa the Marshal had the misfortune to be thrown from his horse. So severe were the injuries he received that it seemed impossible to take him beyond Vittoria, but Larrey, the Emperor's surgeon, ordered him to be wrapped in the bloody skin of a newly killed sheep; so successful was the prescription that the Marshal was soon able to follow the Emperor and rejoin headquarters. On his arrival the Emperor sent him to take over Moncey's corps of thirty-five thousand men, with orders to attack Castaños's forty-nine thousand at Tudela, while Ney, with twelve thousand, worked round the Spanish rear. On the morning of November 28th Lannes attacked the Spaniards at Tudela and won an easy victory, for the Aragonese, under Palafox, thought only of Saragossa, and the Valencians and Andalusians, under Castaños, of their line of retreat to the south. Lannes, seeing the exaggerated length of the Spanish position, at once divined the reason, and drove home an overwhelming attack against their weak centre. Successful as the battle was, it had not the far-reaching effects Napoleon had desired, for, owing to the mountainous nature of the ground, Ney was unable to get across the Spanish line of retreat; however, the enemy lost four thousand men at Tudela and, what was more important, all their artillery.
The battle of Tudela opened the road to Madrid. But when Napoleon arrived there, instead of driving the remnants of the Spanish armies before him and sweeping down to Seville, he found that there was a pressing danger in the north. To give the scattered Spaniards a chance of rallying, Sir John Moore was making a bold advance on Madrid, and was close to Salamanca. Napoleon at once ordered Lannes to hand over his corps to Moncey and to join headquarters. The corps of Ney and a part of Victor's corps were sent off to oppose the English, and on December 28th Napoleon and the Duke of Montebello set out to overtake them. The weather was awful, and the passage of the mountain passes in face of the blizzards of snow tried the endurance of the troops to the uttermost. Lannes, in spite of the fact that he had not entirely recovered from his fall, joined Napoleon in setting an example to the troops. At the head of the column marched the Emperor with one arm linked to Lannes and the other to Duroc. When completely worn out by the unaccustomed efforts and by the weight of their riding-boots, the Emperor and Lannes at times took a brief rest on the limber of a gun carriage, and then got down and marched again.
When Napoleon handed over the pursuit to Soult, he despatched the Duke of Montebello to take command of the corps of Junot and Moncey at Saragossa. On his arrival, on January 22, 1809, the Marshal found that the garrison of Saragossa was in much better heart than the besiegers, for on the west the third corps, owing to illness and fatigue, numbered barely thirteen thousand, and Gazan's division across the Ebro, before the eastern suburb, was scarcely seven thousand strong, while the total strength of the garrison was almost sixty thousand. Consequently Junot and Gazan were seriously contemplating raising the siege. Lannes's first duty was to restore the morale of the troops; to reprimand the general officers, who had been slack in their duty; to set an example to them by his fiery diligence, which refused to let him go to bed once during the whole of the first week he was before Saragossa; to restore the courage of the troops by daily exposing his life in the trenches, and, when necessary, reconnoitring in person with the utmost sangfroid right up to the Spanish positions; supervising hospitals, reorganising commissariat, planning with the engineer officers new methods of sap—in a word, to be everywhere and to do everything. Nothing can more clearly illustrate Napoleon's dictum, "A la guerre les hommes ne sont rien, c'est un homme qui est tout." Within five days of Lannes's taking over command the whole complexion of the situation had altered. The French were making the most resolute assaults with irresistible élan, carrying out the most difficult street-fighting with the greatest zest, sapping, mining, and blowing up convents and fortified posts, fighting above ground and below ground, suffering the most terrible losses, yet ever eager to fight again. By February 11th, thanks to the new morale of the troops, and to the fact that dysentery and enteric were playing havoc in the garrison, Lannes had captured house by house the western half of the town, and had arrived at the Corso. But once again murmurings broke out among the French troops, who had by now lost a fourth of their numbers, and at the same time a strong force of Spaniards under Palafox's brothers threatened to overwhelm Suchet, who was covering the siege. Lannes proved superior to all difficulties; by his fiery speeches and tact he reanimated both officers and men, pointing out to them the triumph they had already won in penning in fifty thousand Spaniards with a mere handful. Then, hurrying off with reinforcements for Suchet, he dug the covering force into an entrenched position on the heights of Villa Mayor, and four days later was back at Saragossa in time to superintend the attack across the Corso. On February 18th the French captured the suburb on the left bank of the river, and thus placed the inner town between two fires.
Disease and the success of their enemies had taken all the heart out of the Spanish defence, and on February 20th Palafox surrendered. Between December 21st and February 21st the Spanish losses had been fifty-four thousand dead from wounds and disease, and Saragossa itself was but a heap of crumbling ruins. Lannes did all in his power to alleviate the sufferings of the unfortunate inhabitants, yet in spite of all his efforts another ten thousand died within the next month. Unfortunately also for his reputation the Marshal, acting on distinct orders from Napoleon, treated his military prisoners with extreme severity and executed two of the most prominent. The great strain of the siege told heavily on the health of the Marshal, who had never completely recovered from his accident near Tolosa; accordingly, after refitting the corps under his command, he handed them over to Mortier and Junot, and at the end of March set out for Lectourne. But his stay there was short, for Napoleon, with the Spanish and Austrian wars on his hands, could not afford to do without his assistance.
By April 25th Lannes found himself once again at the post of danger, but this time on the Danube, at the battle of Abensberg. As he himself said, the first rumour of war always made him shiver, but as soon as he had taken the first step forward he had no thought but for his profession. But, much as he would have liked to dally at Lectourne, and much as he grumbled at Napoleon's overweening ambition once at the front he was the dashing soldier of the first Italian campaign. He arrived in time to take his share in the five days' fighting at Abensberg, Landshut, Eckmühl, and Ratisbon. At Ratisbon he had an opportunity of showing that time had had no effect on his spirit; after two storming parties had been swept away, he called for volunteers for a third attempt: none stepped forward, and he himself rushed to seize a ladder. His staff held him back; but the lesson was not in vain: volunteers crowded to seize the scaling ladders, led by two of the Marshal's aides-de-camp, and soon the walls of Ratisbon were crowned with French soldiers and the town was won.
Napoleon himself accompanied Lannes on the march to Vienna, and the Marshal was perfectly happy. Murat was absent, and there was no evil influence to cloud his friendship with his great chief. Once again Vienna succumbed without a shot, but this time the Austrians took care that there was no bridge over which Napoleon might cross the Danube. Accordingly, the Emperor determined to bridge the river below Vienna, making use of the Isle of Lobau, which lay two-thirds of the way across. The bridge from the south bank to Lobau was built under the personal supervision of the Emperor and Lannes, and on one occasion when they were reconnoitring in person they both fell into the river, and the Marshal, who was out of his depth, was pulled out by the Emperor himself.
By May 20th the French army was concentrated in Lobau, and on May 21st a crossing was effected by several bridges, and assured by Masséna occupying the village of Aspern and Lannes that of Essling. By the morning of the 22nd the mass of the French army had reached the north bank of the river. Napoleon, who perceived that the Austrian line was too extended to be strong, gave the command of the centre to Lannes with orders to sally forth from between the villages of Aspern and Essling and break the enemy's centre. In spite of a devastating artillery fire, the Marshal carried out his orders to perfection, making skilful use of his infantry and cavalry. He had actually forced back the Austrians when he was recalled by Napoleon, who had just heard that the enemy had succeeded in breaking the bridge by sending huge masses of timber down the swollen river. Lannes retreated slowly on Essling, his troops suffering severely from the re-formed Austrian batteries. While thus holding the foe in check the Marshal was struck on the knee by a cannon ball which ricocheted off the ground just in front of him. He was removed to the rear, and the doctors decided that it was necessary to amputate the right leg. The Marshal bore the operation well. He was moved to Vienna, and sent for the celebrated mechanician, Mesler, to make him a false leg, but unfortunately the hot weather affected the wound and mortification set in. The Emperor, in spite of his anxieties, came daily to visit him, and the dying hero had the last consolation of seeing how much he was valued by his august master and friend. The end came soon. On May 30th the Duke of Montebello died, and Napoleon, on hearing the news, with tears in his eyes cried out, "What a loss for France and for me!"