The first campaign was carried out by the new independent government of Guayaquil, which raised an army with local recruits — perhaps 1,800 men strong — and in November 1820 sent it towards the central highlands, with the purpose of encouraging other cities to join the independentist cause.

By February 1821, Guayaquil began to receive reinforcements, weapons and supplies, sent by Simón Bolívar, President of the fledgling Republic of Colombia.

In May of that year, Brigadier General Antonio José de Sucre, Commander in Chief of the Southern Division of the Colombian Army and Bolívar's most trusted military subordinate, came to Guayaquil.

Time was of the essence, as it was vital to force the issue before General José de San Martín, still fighting in Perú, could come up to bring forward any Peruvian claims to the important port-city.

Retaking Cuenca would cut all communications between Quito and Lima, and would allow Sucre to wait for the reinforcements that in the meantime San Martín had promised would come from Perú.

Also, a more progressive and slower advance from the lowlands up the Andes into the southern highlands would allow for a gradual adaptation of the troops to the physiological effects of the altitude.

At the end of the day, the Royalists abandoned the field, while the main body of Sucre's army proceeded to take Riobamba, staying there until April 28, before renewing the advance to the north.

There he proceeded to refit his troops and fill up the ranks with new volunteers from the nearby towns, waiting for the arrival of reinforcements, mainly the Colombian Alto Magdalena Battalion, and new intelligence on the whereabouts of the Royalist army.

In spite of the strenuous efforts made by the troops, the advance up the slopes of the volcano was slower than anticipated, as the light rain that fell during the night turned the trails leading up the mountain into quagmires.

By dawn, to Sucre's dismay, the army had not been able to make much progress, finding itself just halfway along the mountain, 3,500 meters above sea-level, and in full view of the Royalist sentries down in Quito.

Unknown to Sucre, when dawn came, the sentries posted around Quito had indeed caught sight of the Patriot troops marching up the volcano.

During the march up Pichincha, he had detached his crack Aragón battalion from his main force, ordering it to make for the top of the volcano, so as to fall upon the rear of the Patriots when the time came, and break their lines.

As luck would have it, just as it was about to charge down onto the faltering Patriot line, it was stopped dead in its tracks by the English, Scots and Irish veterans of Albión, which made a surprise entry into the battle.

The Colombians reached the outer limits of Quito, but did not go any further, acting on orders from their commanding officer who prudently decided against letting his soldiers enter the city.

While in the general context of the Wars of Independence, the Battle of Pichincha stands as a minor clash, both in terms of its duration and the number of troops involved, its results were to be anything but insignificant.

Previously, when Sucre had recaptured Cuenca, on February 21, 1822, he had obtained from its local Council a decree by which it proclaimed the integration of the city and its province into the Republic of Colombia.

As a consequence, the presence of Bolívar and the victorious Colombian army in the city finally forced the hands of the Guayaquilenos, whose governing council proclaimed the Province of Guayaquil part of Colombia on July 31, 1822.