In 1798, the revolutionary French government conquered Switzerland and imposed a new unified constitution. This centralised the government of the country, effectively abolishing the cantons: moreover, Mülhausen joined France and Valtellina valley, the Cisalpine Republic, separating from Switzerland. The new regime, known as the Helvetic Republic, was highly unpopular. It had been imposed by a foreign invading army and destroyed centuries of tradition, making Switzerland nothing more than a French satellite state. The fierce French suppression of the Nidwalden Revolt in September 1798 was an example of the oppressive presence of the French Army and the local population's resistance to the occupation.