Decembrist revolution ( Argentina ) The Decembrist revolution ( ) was a military coup in the Buenos Aires Province , Argentina . Juan Lavalle , returning with the troops that fought in the Argentine - Brazilian War , made a coup on December 1 , 1828 , deposed the governor Manuel Dorrego and closed the legislature . Dorrego was captured and executed a short time afterwards . The rancher Juan Manuel de Rosas organized militias that fought against Lavalle and removed him from power , restoring the legislature . However , as the coup had reignited the Argentine Civil Wars , Rosas was appointed governor of the Buenos Aires province to wage the war against the Unitarian League . José María Paz made from Córdoba a league of provinces , and so did Rosas . The conflict ended a short time after the unexpected capture of Paz , who confused enemy troops with his own ones . Context . The Argentine Civil War was a civil war that began during the Argentine War of Independence . The conflict was between the federals , who wanted to organize the country as a federation , and the Unitarians , who preferred a centralist government with capital in Buenos Aires . The last military conflict was the 1820 battle of Cepeda ; since then a new constituent assembly was convened to write a new constitution and organize the country . The provinces rejected the 1826 constitution because of its centralist tendencies , and the unitarian president Bernardino Rivadavia resigned . The provinces became a confederation once more , and federal Manuel Dorrego was appointed governor of Buenos Aires . The Banda Oriental had been conquered and annexed by Portugal , which renamed it as Cisplatina ; the Portuguese colonies in South America declared their independence and became the Empire of Brazil shortly after . Both countries began the Argentine - Brazilian War for the control of the province . The peace treaty declared it an independent country , the modern nation of Uruguay , which was disliked by the Argentine military that fought in the conflict . Coup . General Juan Lavalle was initially neither federalist nor unitarian , but after his return he began to be influenced by the unitarians , who tried to gain him for their side . The bulk of the army arrived to Buenos Aires on November 26 , being in a bad shape : they lacked clothing and food , they had unpaid wages since months ago , and resented the peace treaty . There were rumors in the city that the army would revolt against the governor Dorrego , but he dismissed those rumors . The leaders of the revolution met on December 1 to organize the coup , and Dorrego began to reconsider it . But according to the memoirs of Tomás de Iriarte , the minister Tomás Guido prevented the government from organizing a proper resistance . Lavalle ’ s forces gathered in La Recoleta , and began to march at 3 : 30 in the morning , once he got the horses for the cavalry . The admiral William Brown supported the operation and prepared a naval siege of the Fort ( modern Casa Rosada ) , but it was not needed . Lacking any means of defense , Dorrego escaped to the countryside . A group of soldiers occupied the Buenos Aires Cabildo and another secured the police . It was unclear if the Fort would begin a resistance , but once the departure of Dorrego was known , the revolutionaries claimed victory and played a military march . The disputes between the revolutionaries began immediately : Lavalle had promised to be just the military leader of the operation , but now he intended to be appointed governor . A voting organized in the Cabildo by the military , attended only by supporters of the coup , proclaimed Lavalle interim governor , and the military forces in the Fort gave up the resistance at 13 : 00 , accepting Lavalle ’ s rule . The Hall of Representatives , the legislature of Buenos Aires , was closed . There was no active resistance in the city . Lacking leadership , several groups of federals left the city and sought the help of the rancher Juan Manuel de Rosas to organize the resistance against the coup . According to Iriarte ’ s memoirs , Lavalle was informed that all the countryside was against the coup , so he appointed William Brown interim governor and left the city with 600 cuirassiers . Dorrego met with Rosas on December 6 , and the unitarian Gregorio Aráoz de Lamadrid met them a pair of days later , proposing peace negotiations . According to Lamadrid ’ s memoirs , Rosas initially rejected the proposal , considering Lavalle an outlaw , but finally agreed to send delegates to negotiate . Rosas and Dorrego did not agree on the military movements . Dorrego wanted to head the forces to battle against the unitarians , and Rosas preferred to avoid a battle at the moment , and retreat to the Santa Fe province to request support from the federal governor Estanislao López and wait for the dispersed militias of the countryside to join them . Without an agreement , they divided their forces and headed each one to each destination . Dorrego was defeated at the battle of Navarro , and then betrayed by his officers Bernardino Escribano and Mariano Acha , who defected from the federals to the unitarians and took him prisoner to Lavalle . Dorrego was not sent to Buenos Aires for a trial . The unitarians Juan Cruz Varela and Salvador María del Carril wrote mails to Lavalle instructing him to execute Dorrego . Varela requested him to destroy the mails after reading the , but Lavalle kept them . Dorrego was executed in Navarro on December 13 , 1828 . The execution of Dorrego generated a huge controversy in Buenos Aires . Varela wrote a new mail to Lavalle , instructing him to forge documents to make things seem as if he had conducted a trial in Navarro , but Lavalle kept this mail as well . The federals saw Dorrego as a martyr and increased their rejection for the military government . The National Convention in Santa Fe ( the highest national authority at the time ) rejected the coup and the execution of Dorrego as crimes of high treason against the state , and appointed Estanislao López the leader of the troops that would be sent to remove the government in Buenos Aires . The provinces of Córdoba and Entre Ríos joined the offensive , and then the others . The government in Buenos Aires began a campaign of political repression against all federals . Lavalle was soon reinforced by general José María Paz . The number of deaths caused by the political repression was so high that in 1829 Buenos Aires had a higher number of deaths than births . José de San Martín returned from Europe at this time . When he knew of the resign of his political enemy Rivadavia he sailed back to Buenos Aires , to take part in the war against Brazil . The end of the conflict , the Decembrist revolution and the execution of Dorrego took place during his journey : once in Buenos Aires , he disliked the ongoing conflicts and did not leave the ship . Lavalle proposed him to be the new governor of Buenos Aires , but he refused to take part in a civil war , and returned to Europe . Lavalle and Paz move their armies to Santa Fe and Córdoba each one . López managed to force Lavalle to sent his troops to a region rich of mío mío , a toxic grass : five hundred horses died , half of his cavalry . Lavalle attempted to return to Buenos Aires , and met Rosas and López at the battle of Márquez Bridge , where he was defeated . López returned to Santa Fe , because Paz had successfully conquered Córdoba and feared that his province may be next . Completely defeated , Lavalle headed unescorted to Rosas ’ base of operations and requested to parley with him . It was late and Rosas was not there at the time , so he was allowed to sleep at Rosas ’ bedroom . When he woke up , Rosas was next to his bed and invited him with a mate . Lavalle , regretful of the execution of Dorrego , agreed to step down from power . They signed the Cañuelas Pact , calling for elections of members of a new legislature . Lavalle would stay as governor during the transition . They proposed an unified ballot , with both federal and unitarian candidates . The unitarians did not accept the pact : they rejected the action of Lavalle and proposed a new ballot instead , composed entirely of unitarians , and attempted to impose it with electoral fraud . Lavalle , in turn , rejected the unitarians that defied the pact , and called them “ enemies of peace " in a mail to Rosas . Lavalle and Rosas began to write mails to each other , in friendly terms , trying to coordinate the actions to end the conflict . Lavalle proposed to retire the most violent federal candidates of the joint ballot and replace them with moderate unitarians . Still , unitarians did not accept the proposal and imposed their own ballot . Federals prepared to renew the war , but it was not needed . To prevent further hostilities , Lavalle signed a new convention with Rosas . Instead of calling for elections to appoint a new legislature , they agreed to simply restore the old one , closed at the beginning of the decembrist revolution . Juan José Viamonte , a moderate federal , was appointed governor . Lavalle left Buenos Aires and moved to Montevideo , Uruguay ; many federals that were exiled or left the country began to return . A group of federals , including Viamonte , wanted to hold elections for a new legislature , but Rosas pointed that the terms of the deposed legislators had not ended yet and that they were not legally interrupted ; his position prevailed . The legislature met on December 1 , 1829 , a year after the coup . But although the unitarians had been defeated in Buenos Aires , Paz was still in control of Córdoba and defeated Quiroga at the battle of La Tablada . Colonel Smith attempted to mutiny and take his unit to Córdoba , his attempt was thwarted but generated great concern in the city . The legislature voted to release the sum of public power to the governor to deal with the crisis , as it had happened with many governments in the city since 1811 . A pair of days later they appointed Rosas the new definitive governor . Government of Rosas . The state funeral of Manuel Dorrego was held soon after Rosas became governor . He faced the military threat of José María Paz , who began a campaign against federals in Córdoba similar to the one of Lavalle . His actions were not limited to the province of Córdoba , and sent Gregorio Aráoz de Lamadrid to la Rioja and Roman Deheza to Santiago del Estero . Quiroga organized a new army and fought against Paz again , suffering a second defeat at the battle of Oncativo . The provinces under the influence of Paz would become the Unitarian League , Paz would style himself the Supreme Chief of the League . In the poor provinces far away from Buenos Aires , both unitarians and federals had problems to keep up their armies . Quiroga ’ s army was larger , Paz ’ s army was smaller but more professional and had other types of needs . Both Paz and Rosas organize armies for the final conflict . Lavalle , Lamadrid and Martín Rodríguez attempt a coup in Entre Ríos , but they fail . Buenos Aires , Santa Fe and Entre Ríos signed a defensive and offensive alliance , the Federal pact . The Corrientes province joined it a pair of months later . The military conflicts begin in 1831 . López heads to Córdoba with 2 , 000 men , Felipe Ibarra returns to Santiago del Estero from Santa Fe , Ángel Pacheco leads the armies of Buenos Aires , and Quiroga moves to Cuyo ( Mendoza , San Luis and San Juan ) . The initial conflicts prove favourable to the federals : Pacheco defeated the forces of Paz , Ibarra and Benito Villafañe liberated Santiago del Estero and Catamarca , there were local federal rebellions in Córdoba and La Rioja , and Quiroga liberated Mendoza . Still , the most unexpected event of the war was the capture of general Paz . He had dressed his soldiers as gaucho s , and during a reconnaissance mission he confused the troops of López ( composed by real gauchos ) with his own ; his horse was entangled and he was taken prisoner . With the capture of Paz , the Unitarian League began to be defeated . López and Balcarce liberated Córdoba on June 11 , and Quiroga headed to Tucumán . José Vicente Reinafé , close to Estanislao López , was appointed governor of Córdoba . All the provinces join the Federal Pact upon their liberation : first Córdoba , Santiago del Estero , La Rioja and the 3 provinces of Cuyo between August and October , and Catamarca , Tucumán and Salta the following year .