The creation in 1836 of the Peru-Bolivian Confederation by Marshal Andrés de Santa Cruz caused great alarm in the neighbouring countries. The potential power of this confederation aroused the opposition of Argentina and, above all, Chile, due not only to its great territorial expanse but also to the perceived threat that such a rich state signified for the area. Diego Portales, arguably the most important Chilean statesman of the 19th century, who at the time was the power behind president José Joaquín Prieto Vial, was very concerned that the new Confederacy would break the regional balance of power and even be a threat to Chilean independence, and so became immediately its enemy.