San Martin crosses the Andes

Jose de San Martin, an Argentine who had served in the Spanish army before returning home in 1812, spent years building the Army of the Andes at Mendoza. In January 1817 he sent it across the mountains in several columns, through passes more than 3,000 meters high, in about a month. The army included professional soldiers, local militia and many formerly enslaved Black men who were freed to fight. On February 12, 1817 it defeated royalist forces at Chacabuco and entered Santiago.¹²

Buenos Aires had broken with Spain in 1810 and declared independence in 1816, but royalist Peru, the stronghold of Spanish power in South America, still threatened it. San Martin reasoned that independence could not be secure until the Spanish were driven from Lima, and that the best route was through Chile and by sea. Chile's own patriots, led by Bernardo O'Higgins, had been crushed in 1814. San Martin's crossing, planned with great logistical care, reversed that defeat.²

After a setback at Cancha Rayada in March 1818, the patriots won a decisive victory at Maipu on April 5, 1818, which secured Chilean independence. A navy built under the British officer Thomas Cochrane then carried the army to Peru in 1820. Lima fell and San Martin proclaimed Peruvian independence on July 28, 1821. After a private meeting with Simon Bolivar at Guayaquil in 1822 he withdrew from public life, leaving the final campaigns to Bolivar. He died in exile in France in 1850.²