That man had decided to intervene on behalf of the Blancos party in Uruguay; he was Francisco Solano Lopez.
Duke Caxias led one nation's forces in this conflict, which began with an offensive through the Mato Grosso province. This conflict was largely decided following the battle of Riachuelo, and one side's leader in this conflict was killed at Cerro Cora. That man had decided to intervene on behalf of the Blancos party in Uruguay; he was Francisco Solano Lopez. For 10 points, identify this conflict which pitted Paraguay and the namesake group of nations, leading to the deaths of over one third of the Paraguayan army.
Duke Caxias led one nation's forces in this conflict, which began with an offensive through the Mato Grosso province.
War of the Triple Alliance