Yatasto relay The Yatasto relay ( ) was the handover of the command of the Army of the North by Manuel Belgrano to José de San Martín , in January 1814 , during the Argentine War of Independence . It is named after the Yatasto relay , a horse relay at the modern Salta Province , but modern historians consider it could have taken place elsewhere . Context . Buenos Aires , a colony city of Spain in South America , ousted the Spanish viceroy in the 1810 May Revolution and began the Argentine War of Independence , sending armies to other areas still loyal to the Spanish monarchy . One of those areas was the Upper Peru ( modern Bolivia ) , but Manuel Belgrano prevented the royalist armies from marching to Buenos Aires with his victories at Tucumán and Salta . However , he was defeated when he tried to counter - attack , at Vilcapugio and Ayohuma . José de San Martín , Carlos María de Alvear and other veterans of the Peninsular War reinforced the armies of Buenos Aires . They influenced the local politics , causing the Revolution of October 8 , 1812 . San Martín had a military victory at the Battle of San Lorenzo against a raid from Montevideo . When Belgrano was defeated , San Martín was appointed his successor as the commander of the Army of the North . Historian Bartolomé Mitre considers it the result of a plot by Alvear , who sought to remove San Martín from the politics of Buenos Aires by sending him to a distant mission . Later historians as Norberto Galasso consider instead that , despite the dangers , heading that army was an honour , pointing that Alvear sought to do so at a later point . Juan Canter points as well that the mailings of the supreme director Gervasio Antonio de Posadas to San Martín were highly respectful . Meeting . San Martín left Buenos Aires in December , 1813 . He had order to relieve Belgrano and send him back to the city , to be judged for the defeats in the Upper Peru . They knew each other before the meeting by mailing each other , with the intermediation of the Spanish José Milá de la Roca . Both of them shared their rejection to absolutism and belonged to the faction of the late Mariano Moreno . It is widely considered that they met at the Yatasto relay , to the point that the event is named after the place . Portraits and other art allusions use that name as well . However , historian Julio Arturo Benencia considers that the meeting could have taken place at the " Algarrobos " relay , two leagues to the west of Yatasto . The exact date in unclear as well , and could have been at either January 30 or January 17 . Initially , San Martín resisted the instructions related to Belgrano : he considered that he was the best military leader in the army , and that his departure would have negative effects on the morale of the troops . Posadas insisted two months later , and Belgrano left the army . As his health was delicate , he did not return to Buenos Aires , moving instead to Cordoba to await the news there . After leaving , Belgrano wrote again to San Martín , advising him to strictly abide to the local religious customs . José de San Martín was partially agnostic , and Belgrano feared that the royalists may use this as propaganda against him , as it was done before against Juan José Castelli during the ill - fated first Upper Peru campaign . Aftermath . Manuel Belgrano finally stayed in Luján to await the trial , and wrote his autobiography during that time . All charges against him were dismissed a short time later , as nobody formulated a definite accusation . Then , he was sent to a diplomatic mission to Europe . San Martín stayed only a couple of months in the Army of the North . He considered that guerrilla warfare was a better option to face the royalists , and entrusted Martín Miguel de Güemes to direct the operations in Salta , while the Army of the North stayed in Tucumán . San Martín would move later to Mendoza , where he raised the Army of the Andes with Chilean expatriates . The successful crossing of the Andes allowed San Martín to avoid the harsh terrain of the Upper Peru and attack Lima by sea .