SIDESHOWS IN DALMATIA AND POLAND
The Austrian war plan had included offensive operations into Dalmatia and the Grand Duchy of Warsaw. Although Marmont’s Army of Dalmatia was part of the forces under Eugène, there was little cooperation until the Austrians had retreated from the Adige. Marmont’s immediate task was to contain the greatest number of Austrians and Stojevic and his Croatian Grenzer reserve battalions and Landwehr levies made small advances, but within weeks stalled in the fire of the veteran French divisions. In early May, Marmont counter-attacked into the Lika region of western Croatia. And when the Muslim Bosnians, instigated by Marmont, raided into the almost undefended Military Border region, torching a number of villages, Stojevic’s corps virtually dissolved as men deserted to protect their homes. With Austrian resistance crumbling, he made a fast march along the coastal road to join Macdonald’s forces in Carniola and Styria.17 He arrived near Graz on 26 May where he combined with the weak French rearguard to take Graz that day and pursued the retreating Gyulai towards Feldbach, where orders reached him to move at once in forced marches to Vienna.
Finally, there was the campaign in the Grand Duchy of Warsaw and in Galicia, a sideshow at best, but the only Polish military success of the eighteenth and nineteenth centuries. Commanded by Archduke Ferdinand d’Este, its overly ambitious mission was to knock the Grand Duchy of Warsaw, now ruled by the king of Saxony, out of the war and then, with misplaced expectations of Prussian support, turn west to strike into the French rear. Ferdinand’s VII Corps, 32,000 strong including a major cavalry component of forty-four squadrons with 5,000 troopers, crossed the border on 15 April to begin his advance on Warsaw. Prince Poniatowski commanded the Polish Army, only some 15,000 strong though another 22,000 were serving Napoleon elsewhere. It was reinforced by a small Saxon contingent under GM von Dyherrn. Aware of his numerical inferiority – 14,000 Poles against 26,000 Austrians – Poniatowski had taken up a defensive position at Raszyn, six miles south-east of Warsaw. Defeated after tenacious resistance on 19 April, the Polish commander evacuated the capital, retiring east over the Vistula to the fortified Praga suburb which he successfully held against an Austrian attack on 26 April. At this point the recalled Saxons went north to make their way back home, while Ferdinand sent a detachment north to link up with the Prussians, a futile move. Prussia would not intervene
During the last weeks of April and into May, the Austrian main effort was directed to cross the Vistula and come to grips with the main Polish force, but they made little progress. On 2 May they were repulsed at Gora Kalawara and forced to retreat south, where on 18 May they sustained another defeat when 3,000 Poles forced a 4,000-strong Austrian garrison at Sandomierz to capitulate. Meanwhile, in accordance with their undertaking at Erfurt in 1808, a Russian auxiliary corps moved slowly towards Lublin while in the Austrian rear western Poland and Galicia flared into open rebellion. By 21 June the Austrians had recovered Lemberg, only to be driven out within days by a Russian column. With small-scale engagements continuing, on 9 June Ferdinand was informed about the outcome of the Battle of Wagram and received orders to withdraw west to protect the fortress and depots at Olmütz in Bohemia. Meanwhile, in eastern Galicia the local commander, FML Prince Hohenlohe, with only between 4,000 and 5,000 men, managed to repulse some small Polish detachments and even advance east, reaching Tarnow on 15 July. Here he was informed of the Armistice at Znaim and hostilities ended.18
For the Austrians the Polish campaign had been a dead end, perhaps even a defeat. Poniatowski had tied down substantial Austrian forces and yet there was nothing in Poland that could not have been recovered in the event of victory over Napoleon’s main army. It illustrated the problem created by Austrian strategic decision-makers trying to fight on several fronts with inadequate resources. As for Russia, its intervention had been late and largely concerned with grabbing pieces of Poland, in the process revealing that the alliance with Napoleon was coming under severe strain. Overall, except perhaps for the Italian campaign, the various sideshows in 1809 had but little influence on the central campaign in the valley of the Danube.
CHAPTER FIVE
Aspern–Essling: Napoleon repulsed
THE STRATEGIC SITUATION
Although much had changed since Napoleon had arrived on 17 April at Donauwörth to take charge of the situation in Bavaria to defeat Archduke Charles and force the invading Austrian forces to retreat, he had not broken the enemy army or any of its corps. His capture of Vienna on 12–13 April had also not produced the expected Austrian peace offer. He had driven a thin wedge along the Danube into the Austrian heartland, but his line of communications was vulnerable and required a substantial troop commitment to protect it. Davout’s corps and Vandamme’s Württembergers were deployed along the Danube to protect Napoleon’s southern flank, and Bernadotte’s Saxon 9 Corps, stiffened by Dupas’s small French division, was moving towards the area. In Italy, to be sure, Eugène’s Army of Italy had pushed the Army of Inner Austria east into Hungary, while from Dalmatia, Marmont’s two divisions were moving slowly – far too slowly, the emperor thought – into Styria. But with the main army having escaped through the Bohemian mountains and now reorganizing north-east of Vienna and John reinforcing what Napoleon believed to be his still combat-capable army in Hungary, the emperor’s immediate objective was to prevent the union of these two Austrian armies. Moreover, the Tyrolean revolt was threatening his rear, Germany was restive, there remained the possibility of Prussian intervention and the Tsar was not making any substantial moves to implement the promises he had made at Erfurt. Napoleon’s strategic situation was potentially precarious. His most urgent operational objective was to locate and defeat Charles’s army, but he found himself in almost total ignorance of his enemy’s whereabouts. His light cavalry had failed to locate the enemy and for once his staff had failed to provide adequate geographic intelligence. On 13 May he wrote indignantly to General Henri Clarke, his war minister, that, ‘I must express my extreme displeasure that you have left me without any maps or topographical reports … [of] the neighbourhood of Vienna’. He continued that Clarke was to send the maps, plans, reconnaissance reports and notes concerning Moravia, Bohemia and Hungary – originals, not copies – within twenty-four hours.1
Napoleon clearly realized that his most urgent operational task was to transport his army across the broad Danube, the river in effect serving to mask the location of his enemy. At the same time, it was also evident that the presence of Charles’s main army, now deployed north of Vienna, provided potential offensive opportunities for the Austrians. The most attractive option for Charles was to cross the river upstream and into the French rear and threaten Napoleon’s line of communications, a move that would have forced Napoleon to evacuate Vienna and fight a battle on ground of the Austrian’s choosing. But such an enterprise was far too daring for Charles while his army, having returned to the old column system, was no longer able to fight a mobile battle. Even so, the archduke came under considerable and repeated pressure to take immediate offensive action. Emperor Francis urged him ‘to get the armies scrapping’, while his beautiful but bellicose wife, the Empress Maria Ludovica, complained that ‘Charles has become indifferent to a soldier’s honour and only longs for peace’.2
In fact, Charles had no intention of taking the offensive, especially when an attack by Kolowrat’s II Corps against Bernadotte’s bridgehead at Linz was easily repulsed on 17–18 May. While the archduke let it be known that a cross-river operation was still his ‘favourite project’, he welcomed and most probably inspired his chief-of-staff’s memorandum of 17 May advocating a Fabian strategy. By remaining on the left bank of the Danube, so General Wimpffen argued, the army retained its freedom to manoeuvre. Replacements, stores and matériel were close at hand, and just by remaining in position the army tied down a large part of Napoleon’s total forces. Ultimately Napoleon would have to attack across the Danube and if repulsed his army might well be annihilated during the retreat. On the other hand, if t
he Austrians crossed the river and were defeated, this might well spell the end of the Habsburg state. Therefore, Wimpffen asked, why risk total disaster? ‘Fabius had saved Rome as Daun had saved Austria not through rashness but through delay … these are the examples we should follow.’3
Charles now decided that any French crossing should not be resisted at the water’s edge. The enemy should be allowed to transfer a substantial number of troops into the plain beyond and, with part of his army still crossing, should be concentrically attacked while deploying. Meanwhile, the archduke encamped his army, about 120,000 strong if reserves are included and 98,000 strong if not, on the forward slopes of the Bisamberg.4
At this point, Charles enjoyed numerical superiority in men and guns. With much of his army still dispersed, Napoleon could only immediately muster Masséna’s 4 Corps with its corps cavalry under Marulaz and with Lasalle’s light cavalry division attached. Then there was Lannes’s 2 Corps and Bessières’s cavalry reserve, eighteen regiments of heavy cavalry. Also at hand were elements of the Imperial Guard: six battalions of the newly formed Young Guard commanded by General Philbert Curial, and General Jean Dorsenne’s four battalions of the Old Guard. Finally, Davout’s 3 Corps, perhaps the best line formation in the army, with a strong component of veteran troops, was ordered to march on Vienna.
In all Napoleon’s army for the coming battle comprised 85,000 men. Inferior numbers, however, did not worry the emperor. Archduke Charles’s curiously submissive letter had convinced him that the enemy’s fighting spirit was broken, and he worried above all that the Austrian army might slip away into Bohemia or Moravia.
CROSSING THE DANUBE
Of course, Napoleon was also well aware of the need to transfer his army to the left bank and the day after his troops had occupied Vienna he ordered a crossing at Nussdorf, a few miles upstream from the city. Here the river narrowed, though this made for a very rapid current, and the heights of the Bisamberg dominated the crossing site. Still, an attempt was made to seize the Schwarze Lacken Au, an island close to the left bank. Marshal Lannes ordered General Saint-Hilaire to embark 500 tirailleurs, 250 each from the 72nd and the 105th Line, to seize the island which, unknown to the French, was connected to the left bank by a short bridge. Then, too, the two majors commanding the two detachments did not coordinate their action and left themselves no combat reserve. Within a very short time Austrian reinforcements, the IR 49 Kerpen from Hiller’s VI Corps, arrived and though Napoleon and Lannes, who observed the action, ordered in reinforcements, after six hours of bloody fighting the French were forced to withdraw having lost 96 dead and 386, many wounded, taken prisoner. It was a debacle, though given the location and the lack of deployment space on the opposite bank it would appear that this operation had merely been a reconnaissance in force and perhaps also designed to draw Austrian attention to this sector.5 In this it succeeded. Throughout the coming great battles, Archduke Charles maintained V Corps in this area. Actually, on 11 May, Napoleon had already ordered General Nicolas-Marie Songis, the army artillery commander, to reconnoitre the river line between Vienna and Pressburg to find a suitable crossing location.6
But meanwhile General Henri Bertrand, chief of army engineers, had located a possible crossing site at Kaiser-Ebersdorf some 4 miles downstream from Vienna. Some miles below Klosterneuburg, the Danube divided into four separate channels, a tangle of islands large and small and a number of sand bars providing the opportunity to bridge the wide river in several stages. The largest of these islands below the Schwarze Lacken Au were the Tabor, the Prater, the heavily wooded Lobau and the adjoining Lobgrund islands. The last were roughly 3 miles square, large enough to serve as an assembly area for several corps, with the woods and undergrowth also providing concealment for bridgework. The Lobau crossing was particularly suited for bridging because here the bridgework could be subdivided. From the south bank the distance to a large sand bar, the Schneiderhaufen, was 450 yards; from there to the Lobgrund, an island separated from the Lobau proper only by a narrow channel, was 225 yards. The final stretch, from the Lobau to the left bank across the sluggish Stadler Arm, was but 130 yards wide.
Once across the Danube from the Lobau there was the Marchfeld, a vast flat and fertile alluvial plain, gently sloping up north from the Danube to the foothills of the Bisamberg in the west and north. In the east the river March and an escarpment, the Wagram plateau, delimited the Marchfeld. Coming from the Lobau, the compact villages of Aspern and Essling flank a salient, the Mühlau, the entrance to the Marchfeld proper. Save for some artificial elevations, a couple of yards at best, at Aspern, Essling and Gross Enzersdorf, the immediate terrain on the north bank consisted of meadows interspersed with some woods and thick brush. Most importantly, however, numerous drainage ditches, which interfered with operations by troops in close formations but favoured fighting in open order, cut the area. The Marchfeld was well known to the Austrian staff and frequently had served as a manoeuvre area and here, on the plain and in the foothills, the decisive battles of the 1809 campaign were fought: at Aspern–Essling on 21–22 May and Wagram on 5–6 July.
Worried about the archduke escaping into the interior of the monarchy or linking up with John’s army from Hungary, Napoleon decided on an immediate crossing at the location recommended by Bertrand even though his Engineer Park, specially formed for the 1809 campaign, had not yet arrived. It consisted of nine sapeur companies, three pontonniers units and three companies of miners, and was reinforced by three battalions of marine artificers and 1,200 sailors, commanded by Capitaine Pierre Baste of the French Navy. The reinforced park would not arrive until after Aspern–Essling. Meanwhile the engineers, sappers, miners and gunners of the corps would have to handle the bridging operations.
Napoleon ordered the construction of a single consecutive set of pile and pontoon bridges from Kaiser-Ebersdorf across the various islands and the great sandbar to the Mühlau salient. Relying on a single set of pontoon bridges was a risky undertaking. Experts warned that it was the season when the river, already high though still below the high-water mark, was prone to sudden surges in floodwater because of spring rains and runoff from melting snows in the Alps. They also warned that the current was already swift enough that, from positions upstream, the Austrians could launch ram devices – stone-laden barges, heavy tree trunks and such – to smash the long and flimsy pontoon bridges and trestle across the main channel. Napoleon, however, was not deterred. Entrusting Masséna with constructing the bridges and providing the spearhead of the crossing, Napoleon had materials, ropes, timber and pontoons brought to Kaiser-Ebersdorf. Just above this small town there was a creek suitable for collecting pontoons and building rafts and trestles. By 18 May enough material was at hand for a single and narrow bridge, though anchors and chains were in short supply and makeshift expedients – boxes filled with iron scrap and cannon balls – were substituted.
On 18–19 May elements from Molitor’s division carried by six large boats occupied the Lobgrund and, reinforced the next day, ejected the small Austrian garrison from the Lobau. Also on 19 May engineers linked the Lobau islands to the south bank by a single, rather ramshackle bridge of sixty-eight pontoons, nine rafts and some trestles. That evening 200 voltigeurs rowed across the Stadler Arm to establish a bridgehead in the Mühlau salient, driving back outposts from Klenau’s Advance Guard. By about 6 p.m. the next day, driving in Austrian forward elements with artillery and musketry fire and despite harassing Austrian counter-fire, the pontonniers and sapeurs of Legrand’s division managed to complete the final bridge – three trestle sections and fifteen boats – across the Stadler Arm into the Mühlau. At dusk on 20 May, Molitor’s infantry division and Lasalle’s light cavalry crossed into the salient. While the light horse advanced to reconnoitre, the infantry occupied the villages of Aspern and Essling. Hiller had observed the French crossing and had at once ridden to inform Charles in person that an immediate counter-attack was required. But Charles would not hear of it. Napoleon’s crossing
of the Danube relieved him of having to take the offensive and agreed with his own plans. He waited until the late afternoon but then issued orders to begin moving his corps into positions for the planned concentric attack the next day.
Meanwhile the build-up of French troops on the Lobau continued. Though it had been temporarily interrupted during the afternoon of 20 May when an Austrian ram-barge brought down the bridge span between the Schneidergrund and the Lobau, engineers repaired the breach by evening and Lasalle’s light cavalry division filed across to support Molitor. As dusk fell, Lasalle’s horsemen attempted to explore north of the Mühlau, but Klenau had sent in reinforcements to block their progress and the French cavalry could not penetrate their screen, leaving Napoleon with no intelligence about Austrian positions or movements. This failure of the French reconnaissance effort induced the emperor to believe that the Austrians were retreating and had only left some squadrons behind to screen their movement. Still seeking to confirm the whereabouts of the Austrian army, at midnight he ordered Masséna to climb the church tower at Aspern to assess whether there were any Austrian movements. Detecting but a few campfires on the slopes of the Bisamberg, too few for a large army, he reported that the Austrians were retreating. In reality, of course, they were marching to their new assembly areas.
With the bridge holding during the night and traffic fully restored at dawn on 21 May, Whit Sunday, the emperor, who had moved his command post to the north bank, ordered additional forces into the Mühlau. These were two additional infantry divisions of Masséna’s 4 Corps, Boudet’s and Legrand’s, and two heavy cuirassier divisions, d’Espagne’s and Saint-Sulpice’s, from Bessières’s Cavalry Reserve. These were to be followed by Lannes’s corps, then Masséna’s 4 Corps, the remainder of the Cavalry Reserve and the Imperial Guard, and finally by Davout. But it would not be possible to execute this schedule in full. The Danube had risen almost 3 feet and at 10 a.m. another ram-barge again destroyed the second part of the bridge. By mid morning Napoleon had three infantry divisions, 20,000 men, 8,500 cavalry troopers and 44 guns in the Mühlau bridgehead. The heavy proportion of cavalry reflected the emperor’s intention to pursue a retreating enemy, but meanwhile the French reordered their deployment. Molitor’s reunited division, supported by elements of Legrand’s, took up positions in and around Aspern, while Boudet’s division, temporarily commanded by Lannes, was to hold Essling. The cavalry remained to protect the centre.7
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