Editing Battle of Wagram (section)

===Opposing plans===
[[File:Maximilian von Wimpffen.png|200px|thumb|left|[[Maximilian von Wimpffen]], the Army's Chief of Staff, was influential in defining the Austrian battle plan.]]
Intelligence received on 4 July informed the Archduke that the French had weakened their position at [[Pressburg]], a clear sign that the enemy would launch its operations very soon. At 07:00 on 4 July, Charles wrote to his brother, [[Archduke John of Austria]], whose secondary army was stationed near Pressburg. Charles informed John that the battle was imminent and that it "will decide the fate of our dynasty", ordering him to draw closer to the main army by marching to [[Marchegg]], adding that John should leave behind "all baggage and impedimenta". As chance would have it, heavy thunderstorms delayed delivery of the message, which only got to Archduke John 23 hours later.{{sfn|Castle|1990|p=58}}

Archduke Charles did not seriously consider the possibility that the French could cross elsewhere than north of Lobau island until late on 4 July. When he finally accounted for this scenario, Charles remained faithful to his earlier plan not to move his forces towards the river. Instead, he planned to allow the enemy to move into the Marchfeld, leaving there only the Advance Guard and VI Korps, with orders to delay their deployment, cause disorder and casualties, while gradually moving back. Meanwhile, he was planning to maintain his main body on the naturally strong position on the Wagram plateau, with the rest of his forces further west on the Bisamberg heights, the two positions that Wimpffen and Grünne had favoured all along. Should the French have attempted to attack the forces on the Wagram plateau, the forces present there were expected to resist long enough to allow Charles to fall on the enemy's flank with the forces placed the Bisamberg heights. Conversely, should the enemy have attacked the forces on the Bisamberg heights, the main force on the Wagram plateau would have attacked the enemy's flank. The plan was good enough, but had two major flaws. Firstly, it failed to account for the slowness of the Austrian staff work, which impaired coordination between these forces. Secondly, it left the Advance Guard and VI Corps with an ambiguous objective: if Charles wanted protracted resistance, then these forces were too weak to accomplish such a task; however, if the objective was only brief resistance, then they were too numerous and thus needlessly exposed.{{sfn|Rothenberg|1995|p=151}}

Meanwhile, the French were getting ready to cross, according to detailed crossing plans drawn in advance by the Chief of Staff of the {{lang|fr|Grande Armée}}, ''Maréchal'' Berthier. Napoleon was aware that the Austrians had thrown earthworks between Aspern and Groß-Enzersdorf and planned to cross southeast of these positions and then outflank the enemy fortified line. This meant, however, that his forces had a much longer march before making contact with the enemy. On 4 July, by nightfall, under the cover of a violent thunderstorm that impeded any Austrian observation, Napoleon gave the order for the commencement of the crossing operations.<ref name=Nau35/>