At the same time, the increasing power of radicals in Paris incited revolt in the provinces, with the people of Lyon and Marseille rebelling and the Vendée raising an army to attack the central government and open communications with Britain. Spanish armies crossed the Pyrenees, Sardinian (largely Piedmont-Savoy) armies various Alpine borders, and Austrian armies occupied Valenciennes and forced the northern armies back toward Paris. Britain ordered a naval blockade of France on 31 May.