As a first step the emperor temporarily withdrew all French troops from Lobau except Massena’s IV Corps. The island was then transformed into an entrenched camp, with strong fortifications bristling with at least 129 guns. More bridges were built, sturdy and strong, that linked Lobau to the mainland, but Napoleon realized the spans were in danger from fireboats or anything else the Austrians might place in the river to damage them. Taking no chances, the French drove poles into the riverbed upstream to catch any floating obstructions dumped into the Danube. Additionally, the Marines of the Guard manned 20 boats, an impromptu Danube River patrol to keep a watchful eye on things.
Napoleon was pleased with the continuing preparations; the bridges that linked the great river’s islands to the mainland were particularly noteworthy. The emperor, normally a hard taskmaster in war, could boastfully say, “The Danube no longer exists; it has been abolished.” At that point, it was simply a matter of concentrating all his forces for the projected knockout blow.
As the weeks went by Archduke Charles did little or nothing, as if he was mesmerized by his victory over the great Corsican. He did refortify Aspern and Essling and placed batteries that overlooked Lobau Island. More artillery was summoned for his field army, and the Landwehr (Austrian militia) was incorporated into his main forces.
Many reasons have been advanced for this delay. Some authorities suggest he was waiting for a German popular uprising against the French, but if he was, by late June he must have realized the waiting was in vain. Others suggest he was waiting for his brother, Archduke John von Hapsburg, and his army to join him. Unfortunately, a Franco-Italian army under Napoleon’s stepson Eugene de Beauharnais and General Jacques MacDonald soundly defeated the archduke at Raab in Hungary on June 14.
Napoleon poured over maps, studied every intelligence report, and analyzed every possible scenario. He had no intention of crossing the Danube in the same spot as he had in May, though it was obvious Charles must have thought he would. Aspern and Essling were fortified, and the approaches to the old French bridgehead were lined with Austrian cannons. There was the problem of Archduke John as well. Even though the archduke had been defeated and reduced in numbers, he still had enough men to tip the scales in Austria’s favor. Eventually he wound up in Pressburg, just 30 miles away from his brother’s main army. If Archduke John’s 13,000 men suddenly appeared on the Grande Armee’s flank, disaster might ensue.
Eventually a plan began to crystalize in Napoleon’s mind. First, he would give every indication that the French army would indeed cross where it had last May. Among other things, he moved his headquarters to the southwest corner of Lobau Island, an action that would be reported to Charles. Next, he sent General Legrand’s division over to the Muhlau salient, the one toehold the French still had on the Austrian-controlled side of the river, a passage that also included 36 guns. But this was only a feint to confuse Charles.
The real crossing point would be farther southeast. The village of Gross Enzerdorf would be the hinge by which the French army would wheel northwest, outflank the Austrian field guns near the old crossing, and simultaneously smash into the Charles’s left flank. At the same time, and this was the beauty of the plan, the French would impose themselves between the main Austrian army and that of Archduke John.
Ideally, Charles would rise to the bait, moving his army forward to the banks of the Danube, preparing for a rematch on the old battlefield, all the while not suspecting he was about to be hit in the flank and perhaps even the rear by a resurgent Grande Armee. Sure enough, Archduke Charles did move forward, at least initially, the white-coated Austrian troops marching through the lush grain fields that ripened in the blazing summer sun.
But Charles started to have second thoughts almost immediately. His troops were now within range of French guns, whose crews lost no time in bombarding the serried ranks. After spending all of July 2 in deliberation, pondering the best course of action, Charles ordered the bulk of the Austrian army to move farther from the river.
For Napoleon, these movements had both positive and negative aspects. On the negative side, the emperor could no longer outflank, and perhaps even smash, the entire Austrian army as he had hoped. Yet there was some good news too: a Danube crossing, once discovered, would not be hotly contested by Charles’s main force.
The new Austrian positions were not without merit, and in fact used the region’s geographical features to great advantage. Much of the Marchfeld was flat, with a rise or two that usually did not measure more than three feet. A meandering stream called the Russbach snaked its way through Marchfeld’s northern border, its steep banks lined with clusters of trees. The Russbach was truly a stream for it was only about 30 feet wide, but the trees and its banks made it an effective moat against cavalry and an impossible barrier for artillery.
Behind the Russbach there was some marshy ground, and after that, the most prominent feature of Marchfeld, the Wagram. The Wagram was an escarpment, a low ridge varying in height from about 60 to 98 feet that lay between the villages of Deutch-Wagram and Markgrafneusiedl. Making the most of this terrain, Archduke Charles placed his I, II, and III Corps on the escarpment behind the Russbach.
The forward positions in front of the Russbach, including the villages of Aspern and Essling, were held by the Austrian VI Korps and Austrian Advance Guard. Thoroughly out on a limb, these units were to delay the French as long as possible then fall back in good order. The VI Korps was then to withdraw to the Bisamberg, a high ridge near the Danube, while the Advance Guard was to retreat to Markgrafneusiedl.
Massena’s IV Corps was to make a great wheeling movement to the left, marching to a position northwest of Aspern at Britenlee. At the same time, Marshal Nicolas Oudinot’s II Corps would hold the French center, advancing to the Russbach just opposite Baumersdorf. The French right was assigned to Marshal Nicholas Davout’s III Corps, disciplined troops who were to move toward Markgrafneusiedl via Glinzendorf. Supporting troops included Prince Eugene’s Army of Italy and Marshal Jean Baptiste Bernadotte’s IX Corps, the latter consisting of Saxons allied to Napoleon.
As a reserve, Napoleon had his Imperial Guard, famed veterans whose bearskin caps were a symbol of French military prowess. He also had his reliable Reserve Cavalry under Marshal Bessieres. The Reserve was mostly cuirassier regiments, shock troops in steel helmets and breastplates and mounted on powerful horses. That did not complete the list of available units. Marshal Marmont’s XI Corps and the Bavarian troops under General Karl von Wrede were still on the Lobau and had not yet arrived at the front.
General MacDonald, son of a Jacobite exile, hoped to distinguish and rehabilitate his image in the unfolding battle. He leaned toward Republicanism, which made him suspect in Napoleon’s eyes. Worse still, he had been close friends with Jean Moreau, who was living in exile and regarded as one of the emperor’s greatest enemies. Attached to the Army of Italy as a kind of shadow adviser to Prince Eugene, MacDonald had been largely responsible for the latter’s triumph over Archduke John at Raab.
As the Army of Italy waited for the main action to start, Napoleon suddenly appeared on horseback. The Italian troops reacted to his presence by lifting their shakoes on the tips of their bayonets and repeatedly shouting, “Long live the emperor!” Napoleon acknowledged the cheers with a salute, but simply gave MacDonald a glance and rose on. MacDonald was somewhat crestfallen.
The first day’s fighting was heavy, see sawed back and forth, and was inconclusive. By 5 pm it seemed as if the battle would have to stop. Both sides had fought furiously most of the day, and some of Napoleon’s men, many of whom were still green conscripts having been called up to fill out the depleted ranks of the Grande Armee, were nearing exhaustion. But the emperor sensed he had momentum and was loath to end the day’s offensive. Bernadotte, Prince Eugene, Oudinot, and Davout would simultaneously assault the Russbach stream line between Deutch Wagram and Markgrafneusiedl and in so doing drive a deep wedge into the Austrian army. Once a breakthrough was achieved, it would be simply a matter of divide and ultimately conquer.
French artillery opened up about 7 PM, signaling the opening of a new and terrible phase of fighting. Baumersdorf, a village on the Russbach, had the misfortune of being near the Austrian center, which made it a primary target for French artillery. The village was held by the 8th Jager and Volunteers of the Erzherzog Karl (Archduke Charles) Legion, who stoically endured a hurricane of metal that soon set many of its buildings afire.