Under the name of the “Columbian Guard,” Bolívar had organized an army, with which he incorporated at Popayán the remnants of the division of General Torres, raising his total force to about 3,000 men. During his march through a hostile country, he was compelled to leave 1,000 sick in the hospitals, and with the rest reached the frontiers of Quito on the 24th March, 1822. Avoiding a conflict with the Pastusos, which had so often proved fatal to the Patriot arms, he turned to the right and tried to find a pass over the River Guáitara, a mountain torrent whose course lies at the bottom of an almost impassable abyss. Finding one suspension bridge cut, he marched to the left in search of another, and on the 7th April came upon the Royalist army under Garcia, strongly posted between the river and the volcano of Pasto. It was already past noon, but Bolívar seeing that to retreat was impossible, attacked the enemy at once. He drew up his army on the plain of Bomboná, and sent a column against the left wing of the enemy, where the ground presented fewer difficulties than on their right and centre. This column being repulsed, then attacked the centre of the position and was almost annihilated in the attempt to force its way through an abatis which covered this part of the Royalist line. Meantime another column, directed against the right wing of the Royalists, had detached a battalion of light infantry, which climbed the face of the mountain and secured a commanding position on the flank of the enemy, on which Bolívar made another attack upon the centre with a battalion drawn from the reserve. This attack was also repulsed, but when night came on the Royalists hurriedly retreated, abandoning their artillery. The Patriots were left masters of the field, but it was a Phyrric victory, they had lost 600 men in killed and wounded, while the loss of the Royalists was not over 250.
Bolívar remained for eight days encamped on the plateau of Bomboná, and then retreated, leaving 300 sick and wounded behind him. During the retreat his losses were very heavy, but at Patia he received reinforcements from Popayán. The climate and the people were both against him; two months he remained inactive, uncertain what to do, when news reached him that Sucre, aided by a contingent of Argentine-Peruvian troops, sent to his assistance by San Martin, had taken Quito. The moment had arrived in which the two revolutions of the North and of the South of the Continent joined hands on the Equator, in accordance with the plan of San Martin.
On the eve of setting out on his first expedition against Quito, Sucre had written to San Martin asking for his co-operation. After his defeat at Ambato, he wrote again, this time to the Peruvian Minister of War, showing the danger which threatened Guayaquil. From Columbia he received a reinforcement of 500 men, but this was quite insufficient to enable him to take the field. Again he wrote to the Protector of Peru, and San Martin now resolved to give him efficient help.
General Arenales, who was president of the department of Trujillo, had a division stationed on the Peruvian frontier of Quito. San Martin sent him orders to march with it to the assistance of Sucre. Arenales was ill, and declined the command, which was then bestowed upon Colonel Santa Cruz, and by a convention the Republic of Columbia undertook to pay the troops, and to supply the places of all who might fall in war. The auxiliary division consisted of about 1,200 men, among them being one squadron of the mounted grenadiers, under command of Lieutenant-Colonel Juan Lavalle.
Sucre left Guayaquil with such troops as he had, and joined the auxiliaries in the Province of Cuenca in February, 1822, forming an army of 2,000 men, and in March went in search of the enemy. While on the march Colonel Santa Cruz received a despatch from the Government of Peru directing him to withdraw from the army at once with his contingent, which strange order arose from the misunderstanding concerning Guayaquil. Santa Cruz showed the despatch to Sucre, who forbade him to act upon it, telling him that he was no longer under the orders of the Protector. Fortunately the officers of the contingent upheld the authority of Sucre, whose firmness on this occasion prevented a great disaster, and a few days later a despatch was received from San Martin himself cancelling the order.
The situation of the Royalists was now very difficult. The Army of Quito, though numbering 2,000 good soldiers, was isolated, and might defend the mountain passes, but was powerless to take the offensive. The affair at Bomboná had greatly depressed the spirits of the Pastusos. Murgeón had died of despair on seeing the untoward course of events, and Aymerich was again in command.
Aymerich detached Colonel Lopez with 1,500 men to protect the western passes. Lopez stationed himself at Rio Bamba, but was out-manœuvred by Sucre, who entered the valley at the foot of Chimborazo. In accordance with his instructions, Lopez avoided an action, and slowly retreated from one impregnable position to another, till on the 21st April, 1822, Sucre managed to gain his rear by an undefended pass. The Royalists retreated to another position behind the town of Rio Bamba. As they were marching, Lavalle took advantage of a faulty manœuvre, and with ninety-six grenadiers charged the whole of their cavalry, 420 in number, and drove them in confusion upon the positions held by their infantry. Then retreating at full trot, he was joined by thirty Columbian dragoons. The Royalist horse having rallied, came down upon him at full gallop, upon which he wheeled round, charged them again, and completely routed them, with a loss of 52 killed and 40 wounded. One Argentine and one Columbian were killed and twenty were wounded, and the Royalist horse were of no further use in that campaign.
The infantry continued their retreat to the inaccessible position of Jalupano. Then Sucre, by a flank march of four days over the snow-covered heights of Cotopaxi, gained the valley of Chilló, 14 miles from Quito, but found the enemy again in an inaccessible position between him and the city. On the night of the 23rd May, during heavy rain, the Patriot army defiled by a narrow road, covered with loose stones, over the slopes of the volcano of Pichincha, and at eight o’clock the next morning reached the heights overlooking the city of Quito, where the steep mountain side below them was covered by a forest of trees and brushwood.
Before the whole army had reached this position the Royalists had ascended the mountain side, and rushed out of the forest upon the 2nd battalion of Peru, which led the van. Colonel Olazabal, who was in command, stubbornly held his ground till his ammunition was exhausted. The position was held by one battalion after another, as it came up, so long as any cartridges were left, but the reserve ammunition was far in the rear, and the Royalists gained ground. A Columbian regiment charged with the bayonet and recovered the position. Then the Royalists advancing under shelter of the trees, endeavoured to turn the left flank of the Patriots, but were in their turn taken in flank by three companies of the Albion battalion and driven back in confusion. Colonel Cordova then brought up his regiment of Columbian infantry, and, with the aid of the Albion, drove the Royalists down the steep mountain side in utter rout. On such ground the cavalry on neither side could come into action, but the Royalist horse, drawn up as a reserve in the suburbs of the city, was attacked later on by the Patriot cavalry and dispersed.
Sucre then summoned the city to surrender. Next day, the 25th May, 1822, Aymerich capitulated. The Royalists lost 160 officers and 1,100 men taken prisoners, 400 killed and 190 wounded, 14 guns, and all their flags. The Patriots had 200 killed, of whom half belonged to the auxiliaries from Peru, and 140 wounded.