French blockade of the Río de la Plata
The French blockade of the Río de la Plata was a two-year-long naval blockade imposed by France on the Argentine Confederation ruled by Juan Manuel de Rosas. It closed Buenos Aires to naval commerce. It was imposed in 1838 to support the Peru–Bolivian Confederation in the War of the Confederation, but continued after the end of the war. France did not land ground forces, but instead took advantage of the Uruguayan Civil War and the Argentine Civil Wars, supporting Fructuoso Rivera and Juan Lavalle against Manuel Oribe and Rosas.