The losses were considerable on both sides, but the sufferings of the besiegers were augmented by the inclemency of the weather. A convoy of ammunition for Carrera was intercepted by Royalist guerillas, thirty miles from the encampment, and delivered to Sanchez, whose supplies were running short. On the 5th Sanchez made another attack upon the advanced battery, which was bravely repelled by Luis Carrera. The Patriot general then ordered an assault upon the town, which was beaten off by the townspeople themselves. The spirit of the Patriot army was broken, deaths and desertions greatly reduced their numbers. Carrera summoned the garrison to surrender. Sanchez replied by proposing an armistice, during which the Patriots should recross the Maule. A council of war was called, and against the advice of Mackenna the siege was raised. On the 14th August the Patriot army encamped on the banks of the Itata, and from this moment their cause declined.
Carrera again fell into the error of dividing his army. He posted one division near the mouth of the Itata, under command of his brother Juan José, to protect the line of the Maule, and O’Higgins was despatched with a weak division to secure the frontier on the Bio-Bio. With the rest of his forces he went to Concepcion, while his guerillas scoured the country in every direction. This was just what suited Sanchez, who could do nothing with a strong force in front of him. He had plenty of irregulars who knew the country well, and split up his force into flying columns to the north and south. The depredations of the Patriots stirred up the resistance of the people, and various detachments were cut up in detail. O’Higgins could not prevent the reconquest of the line of the Bio-Bio and the occupation of Arauco, by which supplies were drawn by the Royalists from Valdivia and Chiloe.
At the end of September Carrera was shut up in Concepcion, and the Patriot army was blockaded in three separate divisions. He ordered their concentration at Concepcion. Juan José Carrera reached the Membrillar near to the junction of the Diguillin with the Itata early in October, where he was forced to entrench himself. Carrera then marched to meet O’Higgins, and joined him at the pass of “El Roble,” some ten miles to the east of Membrillar. The united forces, about 1,000 strong, encamped on ground badly chosen. Sanchez, joining the irregulars with a division from Chillán, attacked them there on the night of the 19th October. In the confusion Carrera jumped his horse into the river and went off to join his brother, receiving a lance wound in his flight. His absence was not noticed, but O’Higgins, after three hours’ firing, led a bayonet charge upon the enemy, and drove them across the river. When Carrera returned to the camp he saluted O’Higgins as “the saviour of the division and of the country,” and in his official despatch spoke of him as “the first of soldiers, capable of uniting in himself the glories of Chile.” These words were his own abdication, his military star was eclipsed.
After this affair Carrera again changed his plan. He left his brother and O’Higgins at the confluence of the Diguillin and Itata, protected by fieldworks, and returned to Concepcion. This destroyed his prestige in the army and in public opinion; the Press gave the signal of general discontent; even from the pulpit the disastrous influence of the three Carreras was condemned.
When Carrera took command of the army his place as Dictator was for a time filled by his brother Juan José; when he also took the field his two colleagues resigned. The Corporations and the Senate then named a new Junta of three, chosen from the Moderate party, two of whom were enemies of Carrera. The new Junta were active in furnishing supplies until the raising of the siege of Chillán and the revolt of the province of Concepcion produced strained relations between them and Carrera.
The capital became excited by the adverse course of the war, and the Liberals of 1811 clamoured for a change in the constitution. The Press advocated the adoption of a more Republican system. On the 8th October a meeting of the corporations, convened by the Junta, confirmed them in power, but directed that the seat of Government should be removed to Talca. Don José Ignacio Cienfuegos, a man of great influence in the South and an enemy of Carrera, joined the Junta, and Larrain, ex-President of the late Congress, and also an enemy of Carrera, was left in charge of the affairs at Santiago. Government had organized in the capital a new battalion officered by their own adherents, and had asked for a supply of arms from Buenos Ayres. The 300 Chilian auxiliaries came back from that city, and the Argentine Government, in return for their services, had decreed that an Argentine auxiliary force of equal number should march to the assistance of Chile. This column, raised in the provinces of Cordoba and Mendoza, crossed the Andes under the command of Don Juan Gregorio Las Heras, and were warmly welcomed. Their first duty was to escort the Junta to Talca, where Colonel Don Marcos Balcarce took command of the contingent.
The Junta, on receiving news of the affair at El Roble, resolved to remove Carrera from the command, and first thought of replacing him by Balcarce, but, yielding to national sentiment, decided to appoint Colonel O’Higgins, whose tried valour and civic virtues gave him great popularity, both in the army and throughout the country. This appointment in February, 1814, had an evil effect upon the army, where Carrera had still many partizans, splitting it into two parties. Carrera left for the capital accompanied by his brother Luis, but on the road they were taken prisoners by a party of Royalist irregulars under Barañao, and carried off to Chillán.
The army of which O’Higgins took command consisted of about 2,500 men dispersed in fractions, disheartened, and badly armed and equipped. On the 31st January a reinforcement of Royalist troops landed at Arauco, consisting of 800 men and six guns under Brigadier-General Gainza, appointed by the Viceroy as successor to Pareja. Eight days later he crossed the Bio-Bio and joined Sanchez at Chillán, without meeting an insurgent on his march.
O’Higgins stationed one division of his army at Membrillar, while with the rest he marched to the line of the Bio-Bio to intercept the supplies of the enemy. This plan was as bad as those of Carrera. Mackenna, left in command at Membrillar, had under his orders on the 14th February, 800 infantry, 100 dragoons, and sixteen guns. Soon after the country around was occupied by the light troops of the enemy, so that he was obliged to make sallies in force to procure supplies and forage. On one of these occasions, when he had taken a considerable number of cattle his rear-guard was attacked by a much stronger force, which was driven off with heavy loss by Las Heras with 100 of the Argentine auxiliaries.
Meantime a Royalist detachment of 300 men had crossed the Maule, and on the 4th March attacked the city of Talca, from which the Junta had already withdrawn. The feeble garrison made a stout resistance under Colonel Spano, a Spaniard who had joined the Patriots in 1809, but was overpowered, Spano dying wrapped in the tricoloured flag he had so bravely defended.