On the 6th of May Bonaparte left Paris to direct the operations of the Army of Reserve. He had already assembled the several parts of that army near Lake Geneva, and had collected vast supplies there, which were to be used by the army in its march into Italy. On his arrival at Dijon, he reviewed the few thousand conscripts and old soldiers at that place. After this review, which was intended to confirm the spies still further in their belief that the Army of Reserve was purely imaginary, he proceeded to Geneva, and thence to Lausanne, at which places the greater part of the army was assembled. On his arrival there, Bonaparte began the final preparations for crossing the Alps. At first, he thought of leading the Army of Reserve into Switzerland, in order to unite it with Moncey's corps, which had been detached from the Army of the Rhine, and thence march through the St. Gothard Pass into Italy. He also considered the plan of marching into Switzerland, and thence of descending into Italy by way of the Simplon Pass. But after receiving the report of General Marescot, who had been sent to examine the several passes of the Alps, he decided to conduct the greater part of his forces over the Great St. Bernard Pass. By taking this route, which was much the shortest, he could reach Milan earlier, and thus gain the great advantage of time.
The plan of Bonaparte was to conduct thirty-five thousand men of the Army of Reserve over this pass into Italy, and to send the remaining five thousand over the Little St. Bernard Pass, which lies in the Alps but a few miles south of the Great St. Bernard. At the same time a small detachment was to proceed from Switzerland into Italy by way of the Simplon Pass; and Thurreau's division of four thousand, which formed the left of the Army of Italy, was to descend from the Mont Cenis Pass and attack the Austrians in the vicinity of Turin. These movements having been accomplished, Bonaparte intended to direct the greater part of the Army of Reserve on Milan, where it was to unite with Moncey's corps, which was marching over the St. Gothard into Italy. Should this part of the plan be successfully executed, Bonaparte then purposed to march south with a strong force, cross the Po near Placentia, and occupy the Stradella Pass. This pass, which is enclosed on the north by the Po and on the south by the spurs that shoot northward from the main chain of the Apennines, is a strong position on the direct road between Alessandria and Mantua. While holding the pass, Bonaparte expected to debouch westward therefrom against Melas, who, he calculated, would advance eastward from Alessandria and meet him in the plains of the Scrivia.
It is clear, from the histories of this campaign, that the plan as here set forth had not been determined on in all its details before the movements began. In fact, until Bonaparte descended the eastern slope of the Alps, he had not fully decided whether he would march directly on Milan, or on Alessandria and the fortress of Tortona, in order thus to bring relief more quickly to Masséna. Circumstances would then determine the matter. But there is little doubt that before leaving Paris he had mapped out in his own mind the essential features of the plan as here set forth. Upon this point Bourrienne, in his "Memoirs of Napoleon Bonaparte," writes as follows:—
"On the 17th of March, in a moment of gaiety and good humor, he (Bonaparte) desired me to unroll Chauchard's great map of Italy. He lay down upon it and desired me to do likewise. He then stuck into it pins, the heads of which were tipped with wax, some red and some black. I silently observed him, and awaited with no little curiosity the result of this plan of campaign. When he had stationed the enemy's corps, and drawn up the pins with the red heads on the points where he hoped to bring his own troops, he said to me, 'Where do you think I shall beat Melas?'—'How the devil should I know?'—'Why, look here, you fool; Melas is at Alessandria with his headquarters. There he will remain until Genoa surrenders. He has in Alessandria his magazines, his hospitals, his artillery, and his reserves. Crossing the Alps here' (pointing to the Great Mont St. Bernard) 'I shall fall upon Melas, cut off his communications with Austria, and meet him here in the plains of the Scrivia' (placing a red pin at San Giuliano). Finding that I looked on this manœuvre of pins as mere pastime, he addressed to me some of his usual compliments, such as fool, ninny, etc., and then proceeded to demonstrate his plans more clearly on the map."
The correspondence of Bonaparte at this time shows that he had a full knowledge of the positions and condition of the Austrian forces in Italy. From information sent him by Suchet, he learned that the Austrian army was greatly scattered; that but a small portion of it was occupying that part of northern Italy between the Po and Switzerland; and that as yet General Melas did not believe in the existence of the Army of Reserve. It was this knowledge which caused the First Consul to believe that he could execute successfully this bold and hazardous undertaking.
From Villeneuve, at the east end of Lake Geneva, the road across the Alps into Italy passes through the towns of Martigny and Saint Pierre, thence over the Great St. Bernard, through the village of Saint Remy, into the valley of the Aosta, and thence it continues along the Dora Baltea River, through the towns of Aosta, Châtillon, Bard, and Ivrea, into the plains of Piedmont. Not far south of the Great St. Bernard lies the Little St. Bernard Pass, which opens also into the valley of the Aosta. In 1800 these two roads were much more difficult of passage than they are at the present time. When Bonaparte crossed the Alps, the road from Saint Pierre to Saint Remy was simply a bridle path over which no vehicle could pass. Even now it would be a hazardous undertaking to conduct a large army into Italy over the Great St. Bernard. Crossing the Alps at an elevation of more than eight thousand feet, the pass lies in a region of perpetual snow and ice, where the glaciers, the shock of avalanches, and the frequent and blinding storms make the passage of troops difficult and dangerous.
Having once reached the fertile valley of the Po, Bonaparte expected to find food and forage there in abundance; but during the march from Villeneuve to Ivrea it was necessary to provide supplies in advance for the army. For this purpose he had collected them at Lake Geneva. He now caused them to be distributed at different points along this route. He also sent money to the monks in charge of the Great St. Bernard Hospital, in order that they should purchase bread, cheese, and wine for the soldiers. At Villeneuve, Martigny, Saint Pierre, and Saint Remy, he established hospitals for the sick and injured. To the foot of the defile at Saint Pierre he sent forward a company of mechanics to dismount the guns and to divide the gun-carriages and caissons into numbered parts for transportation on pack mules. The ammunition too was carried in this way. But the cannon themselves could not be thus transported. For this purpose sledges with rollers had been made, but they were found to be of no use. Finally, the cannon were enclosed within the trunks of trees hollowed out for the purpose. Thus protected, they were dragged across the Alps by the soldiers themselves. A second company of mechanics was ordered to march with the first division and to establish itself at Saint Remy, in order to put together the carriages and caissons, to remount the pieces, and to make the necessary repairs.
On the 14th of May Bonaparte was ready to begin the movement. The Army of Reserve numbered forty thousand soldiers and forty cannon; about four thousand were cavalry. Four corps of the army, numbering thirty-five thousand men, commanded by Murat, Victor, Duhesme, and Lannes, had taken position from Villeneuve to Saint Pierre. A fifth corps, of five thousand men, commanded by Chabran, was in Savoy at the foot of the Little St. Bernard Pass. Bonaparte himself was at Martigny, at which place he issued the orders for the movement. He had sent Berthier forward to receive the divisions on the Italian side of the Alps.
On the 15th of May the movement began. Lannes crossed first. He began his march from Saint Pierre at two o'clock in the morning, in order to avoid as much as possible the danger from the avalanches, which are less frequent in the cool of the day. He reached the summit safely, and his soldiers were pleasantly surprised to find there the bread, cheese, and wine which Bonaparte had provided for them. Lannes halted but a moment at the Great St. Bernard Hospital; he then began the descent and arrived at Saint Remy on the same day. He was followed in turn by the corps in his rear. At the same time Chabran crossed the Little St. Bernard Pass, and Thurreau began to advance over the Mont Cenis Pass. The entire Army of Reserve crossed between the 15th and 20th of May. During this famous passage of the Alps the soldiers were filled with energy and enthusiasm. Though heavily laden, they themselves, by sheer strength, dragged their cannon over the rough and slippery paths. No exertion seemed to tire them. As they pressed on, all were gay and cheerful. As they climbed the mountain side, their spirits rose. With shouts and cheers and songs, they made that Alpine region ring. In that cold, clear air they felt their blood quicken. They felt, too, the energy, the enthusiasm, the magnetism, of their commander. They not only hoped for, but they expected victory. Were they not imitating the daring deeds of the great Hannibal? Were they not about to enter that Italy where their comrades had fought so gloriously before? Were they not commanded by the "Little Corporal," their idol, whose deeds of desperate daring at the bridges of Lodi and Arcole had won their everlasting admiration?
Thus the Army of Reserve crossed the Alps. By the 20th of May all five corps had reached the valley of the Aosta. Owing to the careful preparations made, there had been scarcely any accidents and no serious delays during the passage. But the greatest difficulty was yet to be met. Some distance down the valley of the Aosta, upon a perpendicular rock commanding a narrow defile, Fort Bard had been constructed. Though this fort was garrisoned by only two or three hundred Austrians, it was impregnable and controlled the whole valley. After descending the Great St. Bernard Pass, Lannes had pushed on down the valley, but was stopped by the fire of the fort. At once he made an effort to capture the place, but was repulsed. He soon saw that it could not be taken by force. Though he gained the road that led past the fort, the deadly fire of the Austrians prevented him from advancing. For a time it seemed that this small but formidable fort would stop the progress of the whole army. Lannes was greatly disturbed. He reported the matter to Berthier, and Berthier sent at once a courier to inform Bonaparte of the situation. The First Consul was still at Martigny, where he had remained for the purpose of hastening forward all the artillery and the rear divisions of the army. This news was a complete surprise to Bonaparte. The effect which it produced upon him is thus described by Thiers:—