The battle of the Piave (8 May 1809) was a French victory that effectively forced the Austrians to retreat from Italy, making up for the earlier French defeat at Sacile. At the start of the War of the Fifth Coalition most of northern Italy was ruled by Napoleon as King of Italy, with day-to-day control held by Eugène de Beauharnais. When the war broke out Prince Eugène's Army of Italy was scatted across much of north-eastern Italy, partly to avoid giving the Austrians an excuse to declare war, and partly because the French did not expect the Austrians to move quickly once war did break out.
Much to Eugène's surprise the Austrians moved very quickly. On 9 April envoys from Archduke John issued the declaration of war, and on the following day the first fighting took place, in the Julian Alps. Over the next few days Eugène was forced to retreat west, abandoning a plan to defend the Tagliamento River and concentrating his army at Sacile. If the entire French Army of Italy had been available then Eugène would have had around 65,000 men, while the Austrians only sent 50,000 regular troops in two corps across the Alps, half as many men as Napoleon had expected. On 16 April Eugène attempted to defeat what he believed to be the Austrian advance guard (battle of Sacile), suffered a defeat, and was forced to retreat back to the Adige, reaching his new lines on 22 April. John followed, but at the exact same time Napoleon had reached the Danube, and defeated the Austrians at Abensberg (20 April), Landshut (21 April), Eggmuhl (22 April) and Ratisbon (23 April). The Archduke was ordered to halt his advance, and retreat slowly back across north-eastern Italy.
After a series of minor engagements the Archduke's army took up a new defensive position on the left bank of the River Piave, to the west of Sacile and the original French lines. The new Austrian position was towards the northern edge of the Italian plains, and guarded the route back to Conegliano and beyond that towards the Alps. The Austrian line ran from Ponte Della Priula on the right to a place identified as Rocca-di-Strada (probably Bocca Di Strada, just to the south of Cornegliano, although this place looks to be some way from the river), where the Austrian left blocked two roads to Cornegliano.
On 7 May Eugène reached the Piave. After examining the possible river crossings he decided to use two fords to cross the river. The first, known as the Large House or Lovadina was two miles downstream from the Austrian right at Priula, while the second, at San Michele, was a further two miles downstream. General Dessaix was to command the advance guard at Lavadina, which was to consist of a detachment of light cavalry and a company of voltigeurs. They were to seize a bridgehead and allow the infantry to cross behind them. Further south General Dessais was to command three divisions of cavalry, which was to cross at San-Michele.
Dessaix's attack at Lavadina began at 4 in the morning. A company of voltigeurs from the 84th regiment found no obstacles on the far bank and the rest of the advance guard was able to get across safely. The Austrians didn't oppose the passage, possibly hoping to trap the French against the river, which did rise in level during the battle, making it hard for the last French troops to get across. The Austrian pickets retreated onto their main line, allowing their strong artillery to open fire on the French. Some of the French advance guards got carried away by this easy start to the day, followed some retreating Austrian cavalry and ran into a battery of 24 Austrian guns which inflicted heavy casualties on the French before they could retreat.
Dessaix then prepared to defend his bridgehead. His infantry was formed into two squares, with his artillery in the gap and the cavalry placed to attack the left flank of any Austrian attackers. Archduke John responded by launching a series of heavy attacks on Dessaix's position, but the French were able to hold on for long enough to allow Eugène to get his three cavalry divisions across the river. The cavalry was able to halt the Austrian attacks on the bridgehead, and Broussier's and Lamargue's infantry divisions were then able to cross the river (although rising water levels kept some of Broussier's men on the far bank).
Once the three cavalry divisions were across the river they were ordered to go onto the offensive. General Pully was ordered to attack the 24 gun battery revealed at the start of the battle. The 28th Dragoons (Poinçot) were to lead the attack, while the 29th Dragoons, with Pully at their head, provided the reserves. Elsewhere Sahuc was to attack the Austrian cavalry facing Dessaix. Both attacks were successes. Pully overran the guns, then broke up a force of Austrian cavalry and chased then towards Cornegliano for a mile. The French then ran into a force of Austrian infantry. One squadron from the 29th was nearly trapped, but Pully was able to escape from the trap. Three Austrian generals and an aide-de-camp to the Archduke were captured during this fighting.
With the last cavalry facing Dessaix cleared away by the 6th, 8th and 25th Chasseurs, he was finally able to advance from his bridgehead. The 9th Chasseurs cleared away a force of Austrian cavalry that was blocking the San-Michele ford, allowing Abbé's division to cross. Most of the men Eugène had planned to move across the river were now united on the left bank - the only exception being part of Broussier's division, trapped by the rising water levels, and Baraguey's and d'Hilliers's division, which formed the reserve (although how much use they would have been on the opposite side of the river to the fighting is unclear).
After this first phase of the battle the Austrians reformed on a new line between the Piave and Cornegliano, hoping to take advantage of some high banks on the left and right of the road to the city. Eugène formed his united army up with Abbé on the right and Lamarque on the left. The centre was made up of seven battalions from Broussier's division and one regiment from Durutte's. The light cavalry was to the left of Lamarque, and Dessaix's advance guard formed the extreme left. Finally Pully and Grouchy's cavalry was posted between the centre and the right.
Abbé and Grouchy were the first attack, attempting to outflank the Austrian line. Abbé captured a place called Cisna d'Olme in early French sources, while Grouchy captured the village of Tezze. A general advance by Abbé, Broussier and Lamargue then forced the Austrian infantry into a general retreat, which the Austrian cavalry was unable to halt. The only remaining Austrian strongpoint was a mill at Capana, held by six Austrian battalions. This position withstood several attacks by Lamarque, and only fell when his artillery arrived.
By 8.30 in the evening the Austrians were retreating in some disorder towards Cornegliano. The Archduke attempted to rally his men behind his reserve, but Eugène made one final attack using his artillery and Grouchy and Pully's cavalry. The Austrians abandoned their attempt to rally, and retreated overnight to Sacile.
The battle of the Piave was a hard-fought affair, lasting from four in the morning until eight-thirty in the evening. The French claimed to have inflicted 10,000 casualties on the Austrians, a not impossible figure given the length of the battle, and to have suffered 2,500 losses themselves. Amongst the Austrian dead were Generals Wolfski and Gyulai and Feldmarschalleutnant Wolfski, while Generals Rissner and Lagger were captured.
The defeat forced Archduke John to increase the pace of his retreat. The French won a series of minor actions during the retreat, and by 20 May Eugène had reached Klagenfurt, in southern Austria. By this point both commanders had split their armies. Eugène sent General Macdonald to attack Carinthia, forcing John to send General Gyulai to match him. Eugène would continue to win victories until the end of the war, defeating General Jellacic at St. Michael on 25 May and Archduke John at Raab on 14 June.