The battle of Arcola (15-17 November 1796) was the decisive battle during Napoleon's defeat of the third Austrian attempt to raise the siege of Mantua, and saw Napoleon extricate himself from a very dangerous position. By November 1796 Napoleon's field army was only 28,000 strong. Thousands of soldiers were ill, and reinforcements were scarce. Two previous Austrian attempts to raise the siege had failed, but a new army of 28,000-30,000 men under the command of General Alvinczy was taking shape around Friuli, and 20,000 men were still present in the Tirol.
The Austrian campaign began at the start of November. While General Davidovich advanced down the Adige valley, Alvinczy pushed the French away from the Brenta valley, past Vicenza and into Verona. Napoleon attempted a frontal attack on the Austrians on 12 November (battle of Caldiero), where he suffered a rare defeat. Only the slowness of Davidovich's advance down the Adige saved the French from a total disaster, but by 13 November Napoleon was in real danger, caught between two larger Austrian armies.
Napoleon decided to gamble everything on an attack on the one weak point in the Austrian position – their line of communication back to the east. As Alvinczy advanced towards Verona he was enclosed between the Adige River to his south and the mountains to the north. The only road open to him ran east to Vicenza through Villanova on the Alpone River. Napoleon decided to move east along the south bank of the Adige, cross the river close to its junction with the Alpone and capture Villanova. If he could move fast enough then the entire Austrian army might be forced to surrender, and at the very least Alvinczy would be forced to retreat.
The battle took place around a triangle of swampy land to the north of the junction of the Alpone and Adige Rivers. The swamps extended north as far as Villanova (now part of San Bonifacio), where the road between Verona and Vicenza crossed a narrow band of dry land between the swamp and the mountains to the north. In the west the swamps ended at Belfione di Porcile (now Belfiore). Napoleon's base was at Ronco, on the southern side of the Adige, just upstream from the junction with the Alpone. The village of Arcole, which gave its name to the battle, is on the eastern side of the Alpone.
On 14 November Napoleon left Verona at the head of Masséna's and Augereau's divisions and Guieu's brigade from Vaubois's division. That night his men constructed a pontoon bridge over the Adige, and in the morning drove off a small Croat force on the opposite bank of the river.
The swampy terrain severely limited Napoleon's options. It was crossed by two narrow raised roads, one running to the bridge at Arcole, the other to Belfiore. On 15 November the French crossed the Adige using a pontoon bridge at Ronco and advanced along both roads. Masséna was sent north-west to cover the French left flank at Belfiore, while Augereau, with Napoleon accompanying him, advanced towards Arcole to attack across the bridge.
This first attack across the bridge at Arcole was a failure. The bridge was defended by a detachment of Croat troops in a strong defensive position, and a series of French attacks were repulsed. The exact details of Napoleon's role in the attack across the bridge are disputed, but it seems certain that he attempted to lead one of these attacks in person, and during this attack his horse was forced into the swamp. Napoleon was rescued by his brother Louis and August Marmont, and the attack was called off.
This small defensive force at Arcole saved the Austrian army from a much more serious defeat, for if Napoleon had been able to cross the bridge on 15 November then the French would have been able to block the road at Villenova, trapping Alvinczy. Napoleon had probably not expected that the bridge would be defended, for he made no attempt to outflank it until later in the day, when General Guieu's brigade was sent across the Adige. This force captured the village of Arcole late in the day, but found itself isolated and was forced to withdraw. By the end of the day the French were back around Ronco.
Alvinczy responded to the French attack by sending Provera to attack their left flank at Belfiore, while other troops were moved to Arcole. Masséna defeated Provera's attack, but at the end of the day Belfiore was in Austrian hands.
On the second day of the battle the Austrians were present in much larger numbers, and although the French attacked in strength towards Arcole and Belfiore they made little progress. Augereau and Guieu managed to cross the Alpone just to the north of its junction with the Adige, but were soon forced back by superior numbers, and by the end of the day the French were once again back at Ronco. Despite this lack of French success Alvinczy decided to move his baggage east, just in case he was forced to retreat.
On 17 November Napoleon tried a more intelligent plan. Masséna was once again sent towards Belfiore. A force from Legnago advanced up the left (east) bank of the Adige, joined up with Augereau's division, and then advanced towards Arcole. Jean-Gilles-André Robert's brigade of Masséna's division was sent to attack across the bridge.
The attack on the bridge nearly ended in disaster. The Austrians counterattacked, and forced Robert's brigade back towards Ronco. As the Austrians approached the French pontoon bridge, they were hit in both flanks by the rest of Masséna's force, coming from Belfiore, and by another French force hidden behind the Arcole-Ronco causeway. Most of the attacking force was killed or captured.
The French were then free to renew their advance. Augereau's men were held up for some time, but the deadlock was apparently broken by a small force of French cavalry scouts that had been sent into the Austrian rear to cause confusion. At about the same time Masséna was finally able to win his way over the bridge at Arcole, and Alvinczy was forced to abandon his position and retreat east to Montebello.
Casualties were high on both sides. In a letter to the directory Napoleon claimed that "Never has a battlefield been more strenuously disputed than that of Arcola". The Austrians suffered between 6,000-7,000 casualties during the three days of fighting, the French around 4,000-4,500.
Napoleon's victory at Arcola did not actually end the campaign. On 17 November Davidovich finally pushed on from Rivoli, and forced Vaubois back to Peschiera, at the end of Lake Garda. Napoleon was forced to abandon any idea of pursuing Alvinczy, and instead turned west to defeat Davidovich.
This gave Alvinczy a chance to turn west again, and he reached Caldiero before news reached him that Davidovich had been defeated and was retreating north up the Adige Valley. Napoleon turned back east to face Alvinczy who responded by retreating back to safety. Early in 1796 he made one more attempt to lift the siege of Mantua, but this ended in disastrous defeats at Rivoli (14 January 1797), La Corona (16 January 1797) and La Favorita (16 January 1797). Two weeks later, on 2 February, Mantua surrendered.