The battle of Mondovi (19-21 April 1796) was a French victory that saw Napoleon's Army of Italy break out of the Apennines onto the plains of Piedmont, and that convinced King Victor Amadeus to seek peace. Napoleon's Italian campaign had only begun on 10 April. Over the next few days he had defeated the Austrians at Montenotte (12 April) and Dego (14-15 April) and the Piedmontese at Millesimo (13-14 April). A setback at Ceva (16 April) had only been temporary, and the Piedmontese army had abandoned that position and fallen back to the last defendable ridge within the Apennine mountains.
Colli picked a very strong defensive position on the western (left) bank of the River Corsaglia. This river flows north into the Tanaro, reaching that river at Lesegno. The Piedmontese left flank was protected by the Tanaro, which was running very high and made an impassable barrier. Their front line ran along the Corsaglia from Lesegno down to the village of San Michele, and was protected by a series of redoubts on the La Bococca ridge, which has a steep eastern front facing the river. A number of detachments extended the Piedmontese right into the hilly ground to the south, with one at the hamlet of Torre. Colli's line of retreat was behind his right flank at San Michele, and followed the road through Vicoforte to the town of Mondovi on the Ellero River, another tributary of the Tanaro.
In the aftermath of the fighting at the start of the campaign Napoleon paused to reorganise his army, and to prepare for an assault on this strong Piedmontese position. The first French attack came on 19 April. General Augereau was sent along the right bank of the Tanaro, while General Sérurier was to attack across the Corsaglia. When Augereau reached the Tanaro he discovered that the river was in flood and the bridges had been destroyed, and his division played no part in the day's fighting.
To the south Sérurier's first attack was repulsed by the guns defending San Michele, but on his left a column under General Jean Joseph Guieu managed to force its way across the river at Torre. This exposed the right flank of the Piedmontese force in San Michele, which was captured before it could retreat onto the heights above the village. If the French had kept their discipline, then the battle was won, but instead they broke ranks to loot the village. This gave the Piedmontese time to organise a counterattack and by the end of the day the French had been forced back across the Corsaglia, although they retained a foothold at Torre.
On 20 April both commanders prepared for their next move. Napoleon decided to renew his attack on 22 April, but on the night of 20-21 April Colli abandoned the lines on the Corsaglia, and began to withdraw through Mondovi. When the French discovered this Napoleon sent Sérurier to pursue the Piedmontese. Colli was forced to turn and make a stand on the plateau of the Brichetto, between Mondovi and Vicoforte, in an attempt to allow his supply train to escape.
Colli's rearguard managed to hold the French on the plateau until about 4.00pm in the afternoon. This didn't stop a small force of French cavalry under General Stengel from making their way around the left flank of the defenders and crossing the Ellero north east of Mondovi. Stengel's men briefly threatened the line of the Piedmontese retreat, but a cavalry counterattack removed the threat and Stengel was killed.
Once the defenders of the Brichetto had been defeated, the French were free to advance on Mondovi. A small garrison had been left behind, but they surrendered on the same day. Although Colli and a large part of his army escaped, this French victory brought Napoleon into the upper reaches of the Po plains. With the mountains finally behind him, Napoleon began a rapid advance towards Turin that only ended when King Victor Amadeus agreed to the Armistice of Cherasco (28 April), surrendering a number of key fortresses and leaving the First Coalition.
The French lost around 1,000 men on the second day of fighting at Mondovi. The Piedmontese lost around 800 dead and wounded and between 800 and 1,500 prisoners, along with the 350 men lost on 19 April.