Battle of Cerrito The Battle of Cerrito ( outskirts of Montevideo , 31 December 1812 ) , was a battle for the War of Independence of the Viceroyalty of the Río de la Plata , between the royalist forces who had control of the city of Montevideo and the rebel forces of the government of Buenos Aires . Context . In the year 1811 , the forces deployed by the Junta Grande of Buenos Aires and the gaucho forces led by José Artigas had started a siege to the city of Montevideo , which had refused to obey the directives of the new authorities after the May Revolution . The siege had been lifted at the end of that year , when the military situation started to deteriorate in the Upper Peru . The change of power in Buenos Aires to the Second Triumvirate , pushed by the change in the situation in the North front allowed them to restart the siege by October 1812 by the rebel forces , commanded by José Rondeau . There was a second army force by the Uruguay River under the command of Domingo French , besides Artigas ' s militias , who had not yet joined the siege due to disagreements with the political leader of the rebels , Manuel de Sarratea . The siege army took over the city of Colonia del Sacramento the last step to complete the siege of Montevideo . The royalist forces were numerically superior to the siege army , but their fidelity to the cause they were defending was doubtful . The siege army was also low in munitions and armament and lacked reinforcements . Knowing that fact , Spanish general Gaspar de Vigodet decided to effect a massive breakout to confront the enemy , but he had bad timing as just the night before the attack , Rondeau received reinforcements and supplies . Battle . On the morning of 31 December , Vigodet and brigadier Vicente Muesas attacked with 2 , 300 men and 8 cannon . Rondeau , who only had 1 , 000 men and two cannon , had taken a high position on the hill known as " Cerrito " ( " low hill " in Spanish ) . Muesas attacked there , displacing regiment number 6 , under lieutenant colonel Miguel Estanislao Soler , dislodging the rebels from the hill . Next another infantry corps , regiment number 4 , under the command of Ventura Vázquez , established a precarious hold on the position . Soler gathered his soldiers , composed almost exclusively of freed slaves , and counter - attacked uphill . This surprise attack paralysed the royalists , and brigadier Muesas was shot to death , causing great confusion among his men . The royalists were dislodged from the hill and while running downhill , they were attacked by the rebel cavalry under Rafael Hortiguera , completing the rout and the enemy ' s retreat . Consequences . The royalists lost 100 men , 146 wounded and 30 prisoners , to the rebel 90 dead , 40 prisoners and one cannon lost but they were left demoralized by the defeat at the battle , and they did not attempt any other breakout from the city walls , not even a year later when Artigas abandoned the siege for a serious political disagreement with the government of Buenos Aires , leaving part of the site undefended , they dared attack Rondeau again . The victory at Cerrito was a defining point for the future operations on land . The city of Montevideo , still held strong , supplied via the Río de la Plata with food and reinforcements . This situation lasted until 17 May 1814 , with the naval victories of Admiral William Brown , which forced Vigodet to surrender to an army marginally bigger than the one Rondeau had . Rondeau was promoted to general , and later given command of the Army of the North , and two times the post of Supreme Director of the United Provinces of the Río de la Plata . Soler was promoted to colonel and later would reach the rank of general . Vázquez was promoted to colonel , and commander Hortiguera to lieutenant colonel , reaching the rank of colonel later .