His enterprise, however, against Provence still took place.

A numerous army of imperialists invaded that country, under his command and that of the marquis of Pescara.

They laid siege to Marseilles, which, being weakly garrisoned, they expected to reduce in a little time; but the citizens defended themselves with such valor and obstinacy, that Bourbon and Pescara, who heard of the French king's approach with a numerous army, found themselves under the necessity of raising the siege; and they led their forces, weakened, baffled, and disheartened, into Italy.
Francis might now have enjoyed in safety the glory of repulsing all his enemies, in every attempt which they had hitherto made for invading his kingdom; but as he received intelligence that the king of England, discouraged by his former fruitless enterprises, and disgusted with the emperor, was making no preparations for any attempt on Picardy, his ancient ardor seized him for the conquest of Milan; and notwithstanding the advanced season, he was immediately determined, contrary to the advice of his wisest counsellors, to lead his army into Italy.
He passed the Alps at Mount Cenis, and no sooner appeared in Piedmont than he threw the whole Milanese into consternation.

The forces of the emperor and Sforza retired to Lodi; and had Francis been so fortunate as to pursue them, they had abandoned that place, and had been totally dispersed;[*] but his ill fate led him to besiege Pavia, a town of considerable strength, well garrisoned, and defended by Leyva, one of the bravest officers in the Spanish service.

Every attempt which the French king made to gain this important place proved fruitless.