Battle of Maipú Battle of Maipú The Battle of Maipú () was a battle fought near Santiago, Chile on April 5, 1818 between South American rebels and Spanish royalists, during the Chilean War of Independence. The Patriot rebels led by Argentine general José de San Martín effectively destroyed the Spanish forces commanded by General Mariano Osorio, and completed the independence of the core area of Chile from Spanish domination. In 1817, the Argentine General José de San Martín led an army across the Andes and defeated the Spanish at the battles of Chacabuco and Chalchuapa and captured Santiago. The Spanish viceroyalty sent a
José de San Martín Nearly 700 expeditionary soldiers of New Granada deserted and joined the patriots. Several populations in the north of Peru supported San Martín, and Arenales defeated the royalists at the Battle of Pasco. More than 300 royalists joined the patriots, including Andrés de Santa Cruz. However, the plans did not fully work as intended. The native populations that joined Arenales could not resist the royalist counter-attacks, and the slaves did not join the army in the expected numbers. The Argentine provinces could not send the supporting army that San Martín had requested earlier, and the Army of the North no longer