The French king treated Victor Amadeus almost as a vassal, and obliged him to persecute his Protestant (Waldensian) subjects.
In 1685 Victor was forced by Louis to persecute his Waldensian subjects, because they had given shelter to the French Huguenot refugees after the revocation of the edict of Nantes.
With the unwelcome help of a French army under Marshal Catinat, he invaded the Waldensian valleys, and after a difficult campaign, characterized by great cruelty, he subjugated them.
The Waldensian valleys lie to the south-west of Turin, in the direction of Monte Viso, but include no high or snowy mountains, while the glens themselves are (with one or two exceptions) fertile and well wooded.