San Martín: Crossing the Andes

José de San Martín, an Argentine-born officer who had served in the Spanish army in Europe, brought a different strategy to independence. Rather than attack royalist Peru directly through Upper Peru, where Argentine forces had repeatedly failed, he trained an Army of the Andes in Mendoza and in early 1817 crossed the mountains into Chile. Victory at Chacabuco in February 1817 and Maipú in April 1818 secured Chile's independence, with Bernardo O'Higgins as supreme director.

San Martín then attacked Peru by sea with a fleet commanded by the British admiral Thomas Cochrane and proclaimed Peruvian independence in Lima in July 1821. Compared with Bolívar, San Martín was a cautious strategist who favored constitutional monarchy for some new states and avoided seeking personal power. His approach shows that independence leaders disagreed about what kind of governments should follow.