The Campaign of Marengo, With Comments

by Herbert H. Sargent

At the outset an Austrian army of one hundred thousand men, led by a courageous commander, was in possession of northern Italy. Everywhere Melas had defeated the French. Masséna at Genoa was about to surrender; and Suchet along the Var was fighting desperately to prevent the invasion of France. Melas, encouraged by these successes, looked hopefully forward to new triumphs. Such was the situation when Bonaparte entered Italy with his columns, numbering in all a little less than sixty thousand men. With these forces he plunged into the Austrian theatre of operations, and in a month ended the campaign. He so manœuvred that a victory of twenty-eight thousand Frenchmen over twenty-nine thousand five hundred Austrians decided the fate of one hundred thousand Austrians and gained for him the greater part of northern Italy.

How, in so short a time and with so few forces, did Bonaparte accomplish such results? In these comments an attempt will be made to answer this question. It is our purpose to analyze somewhat critically the strategical manœuvres of Bonaparte, to compare the things he did with what he might have done, and to show why the whole of northern Italy fell into his possession as a result of the victory at Marengo. It is our purpose, also, to discuss the battle of Marengo from a tactical point of view, and to set forth some of the reasons why the battle, lost in the morning, was won in the afternoon.

The portion of northern Italy then occupied by the Austrians is divided by the Po and Apennines into three unequal parts, through all which roads pass eastwardly from the French frontier to Mantua. Bonaparte, having decided to lead the Army of Reserve into Italy, might have adopted any one of three plans. He might have marched into the southern part of the Austrian theatre of operations, lying between the Apennines and the Gulf of Genoa; or into the middle part between the Apennines and the Po; or into the northern part between the Po and Switzerland. Let us examine each of these plans, in order to determine, if possible, which would have procured him the greatest advantages.

Inasmuch as the mountainous and narrow strip of country lying between the Apennines and the sea was peculiarly fitted for the operations of an inferior army, composed mostly of infantry, and inasmuch as the Army of Reserve was deficient in both cavalry and artillery, it might seem that Bonaparte should have united his army with Suchet's forces on the Var for an attack against Melas. But other considerations deterred Bonaparte from doing so. His objections to this course were that even if he succeeded in forcing the crossings of the Var, the Austrians, as they fell back from position to position, would be constantly re-enforced, and could maintain the siege of Genoa. And again: if he succeeded in driving them across the Apennines and in defeating them at Genoa, they could still fall back along their communications to their base of operations on the Mincio, where they would be protected by Lake Garda on one side and by the fortress of Mantua on the other. Even should the Army of Reserve and all the undefeated portions of the Army of Italy be united into one army, Bonaparte's total strength would not exceed seventy thousand men. With this force he could hardly expect to defeat one hundred thousand Austrians flushed by their recent successes. Furthermore, by adopting this plan, no opportunity would be offered him of severing the Austrian communications.

"An ordinary general," says Jomini, "alarmed by the victorious attitude of the Austrians in Piedmont, would have gone in all haste by Dauphiné toward Provence, and made the Alps the theatre of operations. But Bonaparte appreciated too well the difficulties of a frontal attack. He preferred to cross the mountains upon the rear of the imperial forces and gain the Ticino unopposed, where his presence could not fail to recall his adversaries, and compel them to accept battle with all the chances of success against them."

In order to accomplish this result, Bonaparte had purposely led Melas to believe that the Army of Reserve was intended to re-enforce the Army of Italy. Though Melas did not believe in the existence of an army of reserve, he knew that an effort was being made to organize troops in France, and he believed that they would eventually be sent to join Suchet. But the First Consul had no intention of doing what Melas expected him to do. It was necessary to the success of Bonaparte that he should conceal as much as possible his own purposes, in order to be able to surprise his adversary. In war it is always wise to lead the enemy to believe that an attack will be made in a different direction from that intended. "In whatever way strategy is employed," says Colonel Maurice, "surprise and concealment are essential to success. On this account it will continually happen, in selecting a line of operations or a scheme of campaign, that the most important point of all is to carry out just what an enemy does not expect. Very often successful campaigns, the method of which has been subsequently much criticised, have owed their success to the fact that, from a nice calculation of time and distance, the successful general has seen that he could carry through an operation dangerous in itself, but sure not to be the one expected by his opponent. For the same reason, in all the brilliant and successful efforts of strategic skill, steps have been taken beforehand to carry out the preliminary movements of an army in such a way as to leave an enemy up to the last moment uncertain in what direction the blow would be struck."

Had Bonaparte marched into the middle part of the Austrian theatre of operations, it would have been necessary to cross the Alps over the Mont Cenis Pass. The objections to this plan were that the country lying between the Apennines and the Po contained the strong fortifications of Turin, Coni, Alessandria, and Tortona, which would enable the Austrians to hold Bonaparte in check long enough for Melas to concentrate his scattered forces. Furthermore, by entering Italy over this pass, Bonaparte would approach the centre of the Austrian line, which would enable the Austrians to concentrate against him more rapidly than if he moved against either flank of their position. Again: since the Austrians held the passes of the Apennines, they could delay the advance of the French on Genoa and continue the siege; or, if defeated, could fall back along the great highway leading from Piedmont through the Stradella Pass to Mantua.

Though the great chain of the Alps seemed to present an almost impassable barrier to an army attempting to enter the extreme northern part of Italy from France or Switzerland, Bonaparte did not allow this fact to deter him from his great undertaking. There were several reasons why he adopted this plan.

First: He knew that Melas was not expecting the French to enter this part of Italy.

Second: He knew that the country lying between the Po and Switzerland contained but few fortifications, and was occupied by only a few thousand Austrians.