Gran Colombia – Peru War The Gran Colombia – Peru War of 1828 and 1829 was the first international conflict fought by the Republic of Peru , which had gained its independence from Spain in 1821 , and Gran Colombia , a confederation of the modern - day countries of Colombia , Ecuador , Panama , and Venezuela that existed between 1819 and 1830 . Causes . The issues that led to war were Gran Colombian claims , dating from colonial times , concerning control of the territories of Jaén and Maynas . The Royal Audience of Quito ( ) was established in 1563 by a royal decree of the King of Spain . Its territories included , to the north , Pasto , Popayán , Cali , Buenaventura , and Buga in what is now Colombia . The Royal Audience of Quito was initially part of the Viceroyalty of Peru until 1717 , when it became part of the Viceroyalty of New Granada . Borders at the time were imprecise , especially in the eastern unsettled areas , beyond the Andean cordillera , because of a lack of geographical knowledge and the low importance accorded to these unpopulated and largely inaccessible territories . The first controversy between the Viceroyalty of Peru and the Real Audiencia de Quito erupted in 1802 , when the military and ecclesiastic administration of Maynas was transferred to the Viceroyalty of Peru by royal decree . To this day , there is some dispute as to whether this was a territorial concession as well . This lack of clarity formed the basis for territorial disputes between Ecuador and Peru when , a few years later , these two nations obtained their independence from Spain . Jaén and Tumbez were not included in this royal decree of 1802 . A similar event occurred in 1803 , when the Spanish crown decided that the military affairs of the Province of Guayaquil , whose capital was the port city of the same name , would be run from Lima , Peru . Further , in 1810 , all administrative and economic affairs for the Province of Guayaquil were turned over to the Viceroyalty of Peru , a situation that would endure until 1819 ( and the formation of Gran Colombia , which included Guayaquil . ) " Uti possidetis juris " . Even before the battles for the freedom of the South American colonies were over , Simón Bolivar established the " uti possidetis juris " principle as the basis for the territorial demarcation of the new nation - states that were to be born of the ancient colonial jurisdictions . In essence , the principle , as it applied to the international borders of that time , meant that the borders of the new countries should correspond to the Spanish administrative borders as they were in 1809 . This presented considerable difficulty due to a lack of geographical knowledge , and also because much of the territory in question was unpopulated ( or sparsely populated ) and unexplored . According to the principle , the territory of the Viceroyalty of Lima would then become part of Peru , and the territory of the Viceroyalty of New Granada part of Gran Colombia . However , much of what would become Ecuador fell into a " gray area " with plausible claims by both Peru ( successor to the Viceroyalty of Peru ) and Gran Colombia ( successor to the Viceroyalty of New Granada ) still in conflict . Conflict over Bolivia . The federation of Gran Colombia , formed in 1819 , was the kernel of Bolivar ' s grander scheme to unite the former Spanish colonies in Central and South America . Prior to becoming the titular head of Gran Colombia , Bolivar had been , briefly , the president of the newly independent state of Bolivia , his namesake . Bolivia had formerly been a part of the Viceroyalty of the River Plate , known as Upper Peru , and , once Bolivar relinquished the presidency of Bolivia to his revolutionary compatriot , Antonio José de Sucre Alcalá , in 1826 , the Peruvians saw an opportunity . Early in 1828 , Peru launched a campaign against Bolivia to reclaim its former territory and ultimately forced the Colombians out of Bolivia . Initial engagements . Furious about the news from Bolivia ( that the Colombian army had been expelled ) , President Bolivar resolved to declare war against Peru on 3 June 1828 . Antonio José de Sucre , who had been the President of Bolivia since 1826 , resigned his office ( under duress ) and was appointed Commander of the Gran Colombian Army . The Peruvian declaration of war against Gran Colombia occurred on 3 July 1828 when the Peruvian Government , under President Jose de La Mar , ordered a mobilization of its ground and naval forces . The first engagement of the conflict took place on August 31 of that year when the Peruvian corvette " Libertad " , under the command of Carlos García del Postigo , on patrol in international waters to the west of the Gulf of Guayaquil with the purpose of blockading that port , was attacked by the Gran Colombia n ships " Pichincha " and " Guayaquileña " off Punta Malpelo . The Colombians were forced to retreat with heavy loss of life on - board their vessels . Assault on Guayaquil . The Peruvian squadron , commanded by Admiral Jorge Martin Guise , made a number of raids in the Guayaquil area before directly attacking the defenses of that city from 22 November to 24 November 1828 . In this campaign , he managed to eliminate the Colombian defenses afloat and to silence much of the enemy artillery , but , on the night of the 23 November , the Peruvian frigate " Presidente " ran aground , and the Colombians took advantage of the situation to counterattack . At dawn , with the arrival of high tide , the frigate was refloated under fire . Among the last enemy sniper shots hit Guise , mortally wounding him . Control of the squadron was assumed by his first lieutenant , José Boterín , who continued the siege . The city finally surrendered on 19 January 1829 . After this victory , the corvette " Arequipeña " and the brig " Congreso " repaired to Panama to rescue a Peruvian merchant ship that had been captured by the Gran Colombia ns . Guayaquil would remain under Peruvian occupation until 21 July 1829 . Land war . Peruvian President Jose de La Mar had been born in the city of Cuenca , in present - day Ecuador that was , in 1828 , part of the disputed territory and " de facto " a part of Gran Colombia . Shortly after the siege of Guayaquil , conducted by the Peruvian Navy , was concluded , the Peruvian Army seized the city of Loja by winning the Battle of Saraguro on 13 February 1829 , and then it pushed north into Guayas , the district surrounding the city of Guayaquil . En route , forces under La Mar and General Agustín Gamarra occupied Cuenca as well . Holding Cuenca was , however , short - lived . The Venezuelan general , Antonio José de Sucre , and his compatriot , General Juan José Flores , mounted a counterattack and defeated the Peruvians near the city of Cuenca , at the Battle of Portete de Tarqui on 26 February and 27 February 1829 . Effectively , this ended the major hostilities of the war . Without reinforcement by land , the Peruvian occupation of Guayaquil was destined to fail , but Gran Colombia ' s assertion of rights to the territories of Jaén and Maynas , were similarly frustrated . On 28 February 1829 , La Mar and Sucre signed a conditioning document that became known as the La Mar - Sucre Convention . La Mar however refused to give back Guayaquil or retreat the Peruvian Navy , points that where part of the convention . La Mar proceeded to strengthen his army at his headquarters at Piura while Bolivar prepared to take command of the Colombian army , hostilities seemed about to restart . Aftermath . A coup supported by General Gamarra of the Peruvian Army against President La Mar paved the way for a peace treaty . Subsequently , the Convenio de Girón between Peru and Gran Colombia recognized as borders the " same ones as the corresponding Viceroyalties before independence . " Since this " status quo ante " solution was based on borders that had never been adequately defined , future territorial disputes between Peru and Ecuador and Colombia were virtually inevitable . On 10 July 1829 , the Armistice of Piura recognised the annexation of Guayaquil to Gran Colombia , and , on September 22 of that year , the war between Peru and Gran Colombia officially came to an end when the armistice was ratified . A formal peace treaty , known as the Gual - Larrea Treaty or the Larrea - Gual Treaty , was signed on the very same day , September 22 , 1829 . The " uti possidetis principle " was affirmed , but the text also acknowledges that small concessions by each side may become desirable in order to define a " more natural and precise border " , which is the basis for avoiding further conflict . The parties agreed to form a binational commission to establish a permanent border . Was Gran Colombia a nation or a confederation ? The term Gran Colombia is used today to refer to the federation that was formed between the Republics of Ecuador , Venezuela , and Colombia ( with its province , Panama ) before 1830 . However , Gran Colombia is , in a sense , an artificial term , as the country has always been referred to simply as Colombia . This is clear to anyone who examines the many treaties signed between Colombia and Peru before 1830 . In Peru , however , the dissolution of Gran Colombia is seen as a country ceasing to exist , giving way to the formation of new nation - states . The significance of this view is that the treaties Peru had signed with Gran Colombia became void when the countersignatory ceased to exist . The three new states , the Republic of New Granada ( which later changed its name to Republic of Colombia ) , the Republic of Venezuela , and the Republic of Ecuador , in the Peruvian view , started with a clean diplomatic slate . An alternative view is that Ecuador and Venezuela separated from the Gran Colombia Federation and inherited all of the treaty obligations that Gran Colombia had assumed , as least to the extent that they apply to their respective territories . There are indications that Colombia itself maintained this position , because , clearly , Gran Colombia and the successor state , the Republic of Colombia , shared a capital city , a subset of the same territory , and much the same citizenry . It would be unnatural to disavow their common histories . The question of the status of treaties and accords dating to the revolutionary period ( 1809 – 1819 ) and Gran Colombia period ( 1819 – 1830 ) has a profound effect on international relations up to the present day . Pedemonte - Mosquera Protocol . To illustrate the current relevance of the Gran Colombia – Peru War , Ecuador asserts that there was an agreement signed in Lima between the foreign ministers of Peru and Gran Colombia on 11 August 1830 . Known as the Pedemonte - Mosquera protocol , the agreement , based on the military result at the Battle of Portete de Tarqui and the Gual - Learra Treaty then in effect , settled the placement of the border between the two nations definitively and for all time . Ecuador has used the Pedemonte - Mosquera Protocol as its primary legal support for land claims against Peru . However , Peru disputes its credibility and its very existence . Peru notes that the original document has never been produced by Colombia or by Ecuador . Peru also claims that there is evidence that Pedemonte and Mosquera were not even in the same place on the day in question , so they could not possibly have concluded any agreement at all . Further , according to Peru , the protocol , if it did exist , was never ratified by either country ' s congress . Besides , to the Peruvian way of thinking , even if the protocol was signed , the Gran Colombia Federation had been effectively dissolved well before 11 August 1830 , so any agreement concluded on that day was undertaken by a man without portfolio , that is , a diplomat representing no nation at all . ( Ecuador was born as a country on 13 May 1830 and began its separate existence with the adoption of a Constitution on 23 September 1830 . ) Even though it is unlikely that Ecuador might have concocted an historical treaty of this nature , the Peruvian arguments cannot be dismissed out - of - hand . However , considering the " uti possidetis juris " principle Ecuador would maintain the borders ratified right before Gran Colombia ' s dissolution . Ecuador has produced a copy of the Pedemonte - Mosquera protocol , made in 1870 , that the Colombian embassy in Lima sent to Bogotá . The copy in question was obtained from a diplomat ' s personal collection . However , it has not been satisfactorily authenticated , and it remains in dispute . The Mosquera - Pedemonte protocol is mentioned in a Colombian document titled Legislative Act No . 3 , published 31 October 1910 . This document explains how the borders between Colombia and its neighbors had been established . With respect to its border with Peru , it indicates that the borders are " " those adopted by Mosquera - Pedemonte , in development of the treaty of 22 September 1829 . " "