France's claim on the marquisate, however, was relatively weak, and in the 1580s its possession of the territory came to be contested by Charles Emmanuel I, Duke of Savoy, who had begun pursuing a policy of expansion for his duchy and sought to acquire Saluzzo for himself.

Taking advantage of the civil war weakening France during the reign of his cousin Henry III, Charles Emmanuel occupied Saluzzo in the autumn of 1588, on the pretext of wanting to prevent its occupation at the hands of the Protestant Huguenots of Dauphiné, and continued to hold it for the following twelve years.

To resolve the dispute, Henry IV suggested to Charles Emmanuel two alternatives: the return of Saluzzo to France, or to retain the marquisate but to cede in exchange the county of Bresse, the vicarship of Barcelonnette, and the Stura, Perosa, and Pinerolo valleys.

[4] In response to the French invasion, Charles Emmanuel assembled an army of some twenty thousand Piedmontese, Spaniards, Swiss, and Savoyards, and set out from the Aosta Valley for the Tarentaise in early November.

The citadel of Montmélian, which had held out after the fall of the town, surrendered in mid-November, and a month later the fortress of Sainte Catherine, which had been erected to menace the nearby city of Geneva, was taken and demolished by a joint French and Genevese force.