The Archduke Ferdinand was equally successful. Advancing rapidly into Poland, on April 19th he defeated the Franco-Polish army under Prince Poniatowski and, on the 22nd, occupied Warsaw.
However, the Archduke Charles was not so fortunate. He had assembled six corps in Bohemia and two corps in upper Austria, with the object of invading Bavaria. Davoust was in difficulties, because his troops were scattered far and wide over Germany. But the French Marshals knew far better how to use time than did their enemies. While the Austrians, owing to bad supply organisation, were advancing only by half-day marches, Davoust succeeded in concentrating the major part of his forces on the line Munich-Ratisbon-Wiirzberg. Yet, with only eighty-nine thousand men, he was far inferior to the army the Archduke could bring against him. His situation was then rendered more desperate by an order issued from Strasbourg by Berthier, whom the Emperor had placed in command of the operations in Germany. It was that Davoust should concentrate round Ratisbon.
Roger's relations with Lisala had been deteriorating from day to day, so it was a considerable relief to him when, on April 13th, he left with Napoleon for the front. On arriving at Donauworth, the Emperor swiftly corrected the errors that Berthier had made and, at a risk that he did not at the time appreciate, ordered Davoust to march his four divisions across the enemy's front. At Haussen, on the 19th, the Marshal was fiercely attacked but, by magnificent generalship, fought his way through. There ensued two days of violent conflict between widely separated forces. Then, on the 22nd, at Eckmuhl, Napoleon inflicted a major defeat on the Archduke.
The Austrian centre was shattered. The left, under General Hiller, was driven south-east, towards the river Isar. The main body, under the Archduke, retreated north and, on the 23rd, succeeded in getting across to the left bank of the Danube. But in the five days of fighting in the neighbourhood of Ratisbon, the Austrians had lost forty thousand men in killed, wounded and prisoners.
One of Napoleon's great strengths as a commander of armies was the way in which he succeeded in driving troops, already exhausted by battle, to follow up a defeated enemy. With ruthless determination, he pursued Hiller towards Vienna. On May 13th, the Emperor again rode into the Imperial city as a conqueror.
Nevertheless, the Archduke's army had escaped destruction. Having succeeded in getting across the Danube to the left bank, it was joined by the surviving regiments of Hiller's force and the garrison that had been driven from Vienna. Again a formidable army, it occupied the Marchfeld, some five miles south-east of the capital. It was on this historic field that Rudolph of Habsburg had defeated the famous Bohemian warrior-King Ottakar II in 1276, and so founded the Austrian Empire.
The position not only raised the morale of the troops by its historic association, but was an extremely difficult one to attack; as the river there was from two to four and a half miles wide. Between the banks lay a dozen or more islands, much the largest of which was Lobau. Napoleon decided to cross and occupied the villages of Aspern and Essling, but he was not aware that the Austrians were so close at hand. On May 21 st, Bessieres had barely taken up his position with only seventeen thousand infantry, when they were fallen upon by eighty thousand infantry and fifteen thousand horse. Nevertheless, Lannes succeeded in holding Essling, and it was not until dusk that the Austrians had driven Massena from the centre of Aspern. The Emperor's attempt to break through the enemy's centre by a great cavalry charge failed and, by nightfall, the French positions were almost surrounded.
In the small hours, Massena reopened the battle and drove the Austrians out of Aspern. Meanwhile, the Imperial Guard and Oudinot's Grenadiers had crossed the river. Desperate fighting ensued all through the 22nd. Under one determined onslaught some Austrian battalions began to waver, but the Archduke seized the banner of the Zach regiment and flung himself into the fray. His example rallied his troops, and the French were driven back. In a magnificent charge the French cavalry routed the Austrian cavalry, but were robbed of the fruits of their achievement by themselves being driven back by Austrian Grenadiers.
During the morning, Napoleon received the alarming news that the largest of the bridges which he had built across the Danube had been set on fire, and that others were being swept away by trees and barges sent down the flooded river. This meant annihilation for the French should they fail to hold their own. They were now fighting for survival. Essling was lost, but regained. Aspern finally fell to the Austrians. By then both armies were utterly exhausted. By superhuman efforts the French engineers had repaired a number of bridges. That night the Emperor withdrew the remains of his army into the island of Lobau.
The slaughter had been appalling, approaching that of Eylau. Austria lost twenty-five thousand and France twenty thousand men, among them the irreplaceable Marshal Lannes. The finest assault leader in the army, he had a hundred times led his men up scaling ladders and through breaches made by cannon in the walls of fortresses. He had been wounded more than twenty times, and it was said that bullets only bent, never shattered, his bones; but, at last, he had received a wound that was mortal. Napoleon tenderly embraced the dying Marshal, but Lannes' last words were to reproach him for his boundless ambition which was causing such a terrible loss of French lives. Like many others, for a long time past his heart had not been in the Emperor's wars, and he had continued to serve only out of a sense of duty. A staunch Republican and convinced atheist, he had often openly criticised Napoleon for creating a new aristocracy, and for his rapprochement with the Church.
In this last matter, having paid lip-service to religion in order to gain the support of a large part of the French people, the Emperor had now become so convinced of his absolute supremacy that he could afford to humble the Pope. In Vienna only a week before, on May 17th, he had issued a decree depriving His Holiness of all temporal power, and annexed that part of the States of the Church that he had spared the previous year. Asserting himself to be the 'successor of Charlemagne', he relegated the Pope to merely Bishop of Rome, with a stipend of two million francs. When Pius VII protested and excommunicated him, he retaliated by having him arrested and taken as a prisoner from Rome to Florence.
The battle of Aspern-Essling had a great effect on public opinion throughout the whole of Europe. Eylau had in fact been a stalemate, but Napoleon had been able to claim it as a victory because, on the night following the battle, the Russians had withdrawn. Aspern-Essling was also a stalemate, but in that case it was the French who had withdrawn, leaving the Austrians in possession of the battlefield. The belief that Napoleon, when commanding in person, could not be defeated had at last been deflated.
Had the Archduke Charles been in a position to attack the island of Lobau next day, it could have brought Napoleon's Empire crashing about his ears; for, not only had the majority of the French no more fight left in them, but they were without food and had run out of ammunition. But the Austrians, too, were utterly exhausted; so, under flags of truce, while the battlefield was being cleared of its mounds of corpses, a seven-week Armistice was agreed upon.
While the French army remained on Lobau, the Emperor installed himself in the Palace of Schonbrunn, just outside Vienna, and sent for his Court. During June, by feats of brilliant organisation, he brought from all quarters large reinforcements and huge quantities of stores and ammunition.
Meanwhile, from both south and north bad news for the French kept coming in.
Of the three British Generals court martial led for the Convention of Cintra, Sir Arthur Wellesley alone was acquitted. Lord Castlereagh had a great belief in his abilities and induced the Cabinet to send the future Duke of Wellington back to the Peninsula as Commander-in-Chief of a considerable army.