Buenos Aires faced the French blockade of the Río de la Plata between 1838 and 1840. The Peru–Bolivian Confederation, allied with France, declared the War of the Confederation to Argentina and Chile. Rosas resisted the blockade longer than France estimated he would do, and his strategy of generating disputes between France and England over the blockade eventually gave fruit. France lifted the blockade in 1840, exchanging mutual most favoured nation status between her and the Argentine Confederation.