Battle of Maipú, 1818: the victory that secured Chile's independence

When the battle was decided, San Martín dictated his first report without dismounting, and the army surgeon Diego Paroissien wrote it down with hands stained by the blood of the wounded he had been operating on: “We have just won the action completely. A small remnant is fleeing; our cavalry is pursuing it to the end. The homeland is free.” Three lines closed a campaign that had almost been lost a fortnight before.²

Background: from the Andes to Cancha Rayada

San Martín's plan was continental. He meant to free Chile first, then carry the war by sea to Peru, the strongest seat of royalist power in South America, while Simón Bolívar pressed from the north. In early 1817 he led the Army of the Andes over the mountains from Mendoza and beat the royalists at Chacabuco on 12 February, then entered Santiago.³ › Battle of Chacabuco, 1817

The war was not over. The survivors of Chacabuco held out in the fortress of Talcahuano, and in January 1818 a relief army sent by the viceroy of Peru landed near Concepción under Brigadier Mariano Osorio. Among its units was the Burgos regiment, veterans of the war against Napoleon in Spain. On 12 February 1818, the first anniversary of Chacabuco, the Chilean government under Bernardo O'Higgins proclaimed the country's independence.⁴

Osorio marched north and took Talca. On the night of 19 March 1818 the royalists, led in the attack by General José Ordóñez, fell on the patriot army camped at Cancha Rayada and scattered it in the dark. O'Higgins was hit in the elbow, the patriots lost much of their artillery, and fugitives carried word to Santiago that San Martín was dead and everything lost.⁵

Armies and commanders

San Martín rode for Santiago to show himself alive, calm the city and rearm. Within days the regiments that had kept together on the retreat were back under arms, new munitions and guns were found to replace those lost at Cancha Rayada, and the army took up a position on the plain of Maipú, south of the capital, across the roads by which Osorio had to come.⁶

How many men stood on each side depends on the source. The Argentine government's account gives the United Army 5,400 men and 21 guns. The Instituto Nacional Sanmartiniano, synthesizing several sources, puts it at about 6,000 men and 21 guns against about 5,000 royalists with 12 guns. Bartolomé Mitre, the nineteenth-century Argentine historian, counted a little over 5,000 patriots with 22 guns and gave Osorio 5,500 men, and the newspaper La Gaceta, writing for the bicentenary, follows a similar count of 4,900 patriots against 5,500 royalists.⁷

San Martín commanded in person. Colonel Juan Gregorio de Las Heras led the 1st Division on the right, Colonel Rudecindo Alvarado the 2nd on the left, and Colonel Hilarión de la Quintana the reserve in a second line behind them, while General Antonio González Balcarce had overall charge of the infantry. The artillery was under Manuel Blanco Encalada and José Manuel Borgoño.⁸

The army was Argentine and Chilean, and it was not only white. San Martín had raised battalions of free Black and mixed-race men and freed slaves in Cuyo, and Chilean Black soldiers of the Infantes de la Patria, a unit the historian Hugo Contreras Cruces has studied, also fought at Maipú.⁹

On the other side, Osorio held the supreme command, with José Primo de Rivera as his chief of staff and Ordóñez as his most aggressive subordinate. The core of his infantry was four Spanish and Peruvian battalions: Burgos, Arequipa, Concepción and Infante Don Carlos.¹⁰

The battle in phases

Opening fire. On the morning of 5 April the two armies faced each other across a narrow hollow, the patriots on the crest of the Loma Blanca, the royalists on the rise beyond it near the Lo Espejo farm. Around midday San Martín's guns opened fire first. The royalist batteries answered, gave away their positions, and San Martín sent both wings forward.¹¹

The right wing. Las Heras advanced with the 11th battalion against the hill on the royalist left, while the mounted grenadiers under Manuel Escalada and Manuel Medina charged and drove off the royalist cavalry on that flank.¹²

The left wing. Alvarado's division crossed the hollow and climbed the opposite slope, only to meet the mass of the royalist infantry under Ordóñez. It was thrown back with heavy losses. For a moment the battle hung in the balance.¹³

Turning point: the oblique attack of the reserve

San Martín now did what Maipú is remembered for. He ordered Quintana's reserve forward at once, not straight ahead but obliquely across the low ground, so that it fell on the flank of the royalist infantry that was pursuing Alvarado. The move restored the line on the left while Las Heras kept pressing the other wing.¹⁴

The fighting there was the hardest of the day. The Chilean and Argentine cavalry under Ramón Freire and Santiago Bueras swept the royalist horse off the right of the field, and Bueras was killed in the charge. The Burgos battalion unfurled the colors it had carried at Bailén, the battle in Spain where San Martín himself had fought against the French in 1808, and its men shouted: “Here is the Burgos! Eighteen battles won, none lost!”¹⁵

Osorio, believing the day lost, left the field, and Ordóñez took over. The royalist battalions formed squares and beat off charges of cavalry and infantry, but, surrounded and without cavalry of their own, they began to give ground. Ordóñez led them back in a compact mass, under constant attack, to the walls and vineyards of Lo Espejo.¹⁶

Lo Espejo. The patriots stormed the farm too quickly at first. A battalion of Chilean light infantry sent in along the lane to the buildings was driven back with heavy loss. San Martín had seventeen guns massed on the higher ground; they battered the enemy out of the outer defenses, and the infantry broke through the mud walls and took the houses. The killing inside went on until Las Heras stopped it. Ordóñez, Primo de Rivera and their officers gave up their swords.¹⁷

Before the end O'Higgins arrived from Santiago with about 1,000 more men, his arm still bandaged from Cancha Rayada. The two commanders embraced without dismounting, the scene known ever since as the Embrace of Maipú. “Glory to the savior of Chile!” O'Higgins said, and San Martín replied that Chile would never forget “the illustrious invalid” who had come to the battlefield in that state.¹⁸

Aftermath

The figures for the losses differ. The Instituto Nacional Sanmartiniano puts patriot losses at about 1,000 and royalist losses at about twice that, with some 3,000 prisoners. Mitre, followed by La Gaceta, counts about 1,000 royalists killed and, among the prisoners, one general, four colonels, seven lieutenant colonels, 150 officers and 2,200 men, with more than 1,000 patriots killed and wounded. San Martín paid tribute to both sides in his report: rarely had there been an attack braver, faster and more sustained, and never a resistance more vigorous, firm and stubborn.¹⁹

Osorio escaped south with a remnant of his army. Memoria Chilena calls the victory fundamental to consolidating independence: it broke the royalist army physically and morally, and only minor actions followed in Chile while the country prepared the expedition that would sail from its ports to liberate Peru. That was the next link in San Martín's continental plan.²⁰

Legacy and memory

Mitre judged Maipú the hardest-fought battle of the whole war of independence and ranked its importance with Boyacá and Ayacucho, arguing that neither would have been fought without it. In his view San Martín won it with an oblique attack in the manner of Epaminondas, throwing his reserve against the weakest flank of the enemy. The Argentine government's own account draws the same lesson: Maipú is taught as an example of the timely use of the reserve.²¹

The Embrace of Maipú became a symbol of the friendship between Argentina and Chile, and the two countries still mark the anniversary together. In 2017 the Chilean embassy in Buenos Aires held its commemoration with the Instituto Nacional Sanmartiniano and the Mounted Grenadiers, and in 2018 the armies of both countries marked the bicentenary in Chile.²²

Visiting the battlefield today

The plain where the battle was fought now lies inside the commune of Maipú, part of greater Santiago. Before the battle the patriot army had vowed to the Virgen del Carmen, patroness of the army, that a shrine would rise on the field of victory, and after Maipú O'Higgins kept the promise: the first stone of a chapel was laid on the Lo Espejo lands in November 1818.²³

The work stalled for decades, and the chapel, known as the Capilla de la Victoria, was not finished and blessed until 1892. The great votive temple that stands there today, the National Shrine of Maipú, grew out of the same vow.²⁴