Unfortunate in the choice of his subordinates and unable to retain their confidence; accused of irresolution and even of cowardice; abandoned by Cochrane, who sailed off to Chile and left the army stranded; incapable of restraining his soldiers from indulgence in the pleasures of Lima; now severe, now lax in an administration that alienated the sympathies of the influential class, San Martin was indeed an unhappy figure.

It soon became clear that he must abandon all hope of ever conquering the citadel of Spanish power in South America unless he could prevail upon Bolivar to help him.
A junction of the forces of the two great leaders was perfectly feasible, after the last important foothold of the Spaniards on the coast of Venezuela had been broken by the Battle of Carabobo, on July 24, 1821.

Whether such a union would be made, however, depended upon two things: the ultimate disposition of the province of Quito, lying between Colombia and Peru, and the attitude which Bolivar and San Martin themselves should assume toward each other.

A revolution of the previous year at the seaport town of Guayaquil in that province had installed an independent government which besought the Liberator to sustain its existence.

Prompt to avail himself of so auspicious an opportunity of uniting this former division of the viceroyalty of New Granada to his republic of Colombia, Bolivar appointed Antonio Jose de Sucre, his ablest lieutenant and probably the most efficient of all Spanish American soldiers of the time, to assume charge of the campaign.