the Second Battle of Dego, driving the Austrians northeast, away from their Piedmontese allies. Satisfied that the Austrians were temporarily inert, Bonaparte harried Michelangelo Colli's Piedmontese at Ceva and San Michele Mondovi before whipping them at the Battle of Mondovì. A week later, on 28 April, the Piedmontese signed an armistice at Cherasco, withdrawing from the hostilities. On 18 May they signed a peace treaty at Paris, ceding Savoy and Nice and allowing the French bases to be used against Austria. After a short pause, Bonaparte carried out a brilliant flanking manoeuvre, and crossed the Po at Piacenza, nearly cutting the Austrian line of retreat. The Austrians escaped after the Battle of Fombio, but had their rear-guard mauled at Lodi on 10 May, after which the French took Milan. Bonaparte then advanced eastwards again, drove off the Austrians in the Battle of Borghetto and in June began the Siege of Mantua. Mantua was the strongest Austrian base in Italy. Meanwhile, the Austrians retreated north into the foothills of the Tyrol. During July and August, Austria sent a fresh army into Italy under Dagobert Wurmser. Wurmser attacked toward Mantua along the east side of Lake Garda, sending Peter Quasdanovich down the west side in an effort to envelop Bonaparte. Bonaparte exploited the Austrian mistake of dividing their forces to defeat them in detail, but in so doing, he abandoned the siege of Mantua, which held out for another six months (Carl von Clauswitz mentioned in On War that the siege might have been able to be kept up if Bonaparte had circumvallated the city). Quasdanovich was overcome at Lonato on 3 August and Wurmser at Castiglione on 5 August. Wurmser retreated to the Tyrol, and Bonaparte resumed the siege. In September, Bonaparte marched north against Trento in Tyrol, but Wurmser had already marched toward Mantua by the Brenta River valley, leaving Paul Davidovich's force to hold off the French. Bonaparte overran the holding force at the Battle of Rovereto. Then he followed Wurmser down the Brenta valley, to fall upon and defeat the Austrians at the Battle of Bassano on 8 September. Wurmser elected to march for Mantua with a large portion of his surviving troops. The Austrians evaded Bonaparte's attempts to intercept them but were driven into the city after a pitched battle on 15 September. This left nearly 30,000 Austrians trapped in the fortress. This number rapidly diminished due