The decisive battle of the Chilean War of Independence saw combined patriot forces rout a Spanish royalist army near Santiago, ending organized Spanish resistance in Chile. San Martín reportedly embraced O'Higgins on the battlefield, declaring victory secured. The win effectively guaranteed Chilean sovereignty and became a cornerstone of national identity, still commemorated as a founding triumph.
By 1818 Spain had already lost and regained Chile once, and royalist commander Mariano Osorio hoped to repeat that reconquest. Instead, at the hacienda of Maipú just outside Santiago, the combined Army of the Andes and Chilean patriots inflicted a catastrophic defeat, killing or capturing most of the 5,000-strong royalist force.
Bernardo O'Higgins, still recovering from a wound suffered weeks earlier at Cancha Rayada, insisted on riding to the battlefield despite his injury, arriving as the fighting turned decisively in the patriots' favor. His embrace with San Martín amid the smoke and the dead became one of the most reproduced images in South American independence iconography.
The victory did more than end Spanish military hopes in Chile; it freed San Martín's Army of the Andes to pursue its larger goal of continental liberation, setting the stage for later campaigns into Peru. Chileans still mark Maipú as the true birth of their independent nation, distinct from the 1810 declaration.
Key people: Bernardo O'Higgins, José de San Martín