Book review: Thunder on the Danube, Volume II: The Fall of Vienna and the Battle of Aspern

The first phase of Emperor Napoleon's campaign of 1809 left the Austrian army broken into groups. The main force, under Archduke Charles, retreated north toward the safety of the Bohemian mountains, while the other, led by Johann Freiherr von Hiller, marched along the Inn River. Instead of pursuing the main Austrian group, Napoleon decided to follow the road to Vienna, which he entered on 13 May, 1809—one month to the day after he had left Paris to take charge of the Austrian campaign.
 
The French emperor's decision was strategically correct since it placed him between the armies of Archduke Charles and Archduke Johann, who had defeated Prince-viceroy Eugène de Beauharnais in the battle of Sacile on 16 April. Moreover, the fall of the Austrian capital would have a major psychological impact on the minds of the German patriots, while providing Napoleon's Grande Armée with supplies. The conflicts of revolutionary and imperial France were total wars, which among other things, meant that the French army lived off the lands and cities they conquered.  Knowing that, the Austrians left behind boxes full of counterfeit money when they evacuated Vienna.
 
In part 2 of Thunder on the Danube John H. Gill, retired U.S. Army colonel and author of With Eagles to Glory, focuses his narrative on the Battle of Aspern-Essling. That confrontation began to the surprise of Archduke Charles, who could not believe that Napoleon would advance through the rather isolated Kaiser Ebersdorf site in preference to Nussdorf, with its excellent road network. On the other side, Napoleon had simply neglected to keep up on the exact position of the Austrian army and on its exact numbers.  The result was that in the first hours of establishing a bridgehead on the other side of the Danube River, less than 30,000 French soldiers had to face more than 90,000 Austrian and Hungarian troops.
 
A bridgehead always depends on how quickly one gets as many units as possible across to protect and develop it, and that in turn depends on how secure the bridges are.  Within the first few hours Napoleon realized that the bridges his army had crossed were in danger, both from the flood waters of the Danube itself and materials the Austrians dropped into the river to destroy them. Because of his stubborn will to win the battle at any cost, Napoleon separated his army between the southern and northern banks of the river. Fought on 21 and 22 May, the Battle of Aspern and Essling was the first of many to follow that would involve a high percentage of French casualties, which included Marshal Jean Lannes.
 
For Archduke Charles, who avoided launching a counterattack against the Lobau Island, where the hospital was, the two-day slugfest ended in a defensive victory. In the other sections of the Frontiers, however, the situation went from bad to worse for the Austrians. Gill gives special attention to the series of defeats that Prince-Viceroy Eugène managed to inflict on Archduke Johann army after his failure in Sacile, proving that he did not become viceroy solely because he was Napoleon's stepson. Elsewhere, Prince Jósef Antoni Poniatowski carried out a brilliant series of maneuvers to defeat Archduke Ferdinand's army around Warsaw, while Marshal Auguste Frédéric Louis Viesse de Marmont's small army pushed General-Major Andreas Stoichewich's invading detachment out of Dalmatia. Throughout these events, Gill succeeds in holding the reader's the attention to the last—which merely sets the state for the last act of the campaign. Undoubtedly the third volume of Thunder on the Danube will be good as the first two.