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
Army of the North and 9 artillery pieces could not deal with the 5,100 royalists and 23 artillery pieces and had to escape with about 1,000 casualties, while the royalists only counted 32 dead. Objectives were not met and the provinces were left surrounded by potential enemies. British and French could arrive by sea, Portuguese from the East and Spaniards from the North. Had they conquered Upper Perú, the biggest threat, the royalists, would have been ended. In January 1816, Lieutenant Colonel Gregorio Aráoz de Lamadrid was sent to the north, but on 31 January was defeated at Culpina. On 2 February he won