Battle of Tacuarí The Battle of Tacuarí ( 9 March 1811 ) was a battle in Southern Paraguay between revolutionary forces under the command of General Manuel Belgrano , member of the Primera Junta government of Argentina , and Paraguayan troops under colonel Manuel Atanasio Cabañas , at the time at the service of the royalists . History . After the May Revolution in Buenos Aires , capital of the Viceroyalty of the Río de la Plata , the Primera Junta government invited the other cities and provinces to join the revolution . Any intent of preserving the local governments previous to the revolution were considered hostile ; and as a consequence two military campaigns were launched to suppress the resistance , one to Upper Peru and another to Paraguay , whose Spanish governor , Bernardo de Velasco , had refused to recognize the Junta and had received political support from the Cabildo of Asunción . General Manuel Belgrano , a member of the Junta was named commander of the expedition with only 700 men , half of them without military experience . Even though his forces were small , the extreme prudence of Velasco got them to fight first at Paraguarí , near Asunción , were he was defeated with relative ease . Forced to retreat , Belgrano marched to the Tebicuary river , where he was joined by 400 men from the Guaraní militias from Yapeyú and some men from the Fatherland Cavalry Regiment ( ex - Blandengues ) . As noted in his " Memoirs " , the Paraguayans did not pursue , and he could continue retreating to the town of Santa Rosa . There he received news that the situation was worsening at the Banda Oriental , so the Junta was ordering him to end the Paraguay campaign soon so he could help in the new theater of operations . On his part Belgrano requested reinforcements and decided to stop the retreat at the Tacuarí river and establish a defensive position . He was confident that with reinforcements from Buenos Aires he could maintain the position . The help sent by the Junta consisted of a small naval squadron travelling north on the Paraná River . This flotilla , composed of three small ships under the command of Juan Bautista Azopardo was defeated on March 2 , 1811 at San Nicolás de los Arroyos , so Belgrano was left without reinforcements . The Paraguayans advanced after Belgrano , expecting he would retread without combat after the defeat at Paraguarí . The vanguard was under the command of Fulgencio Yegros and the main army under General Manuel Cabañas , with a total of 2 , 000 men , plus a reinforcement of three pieces of artillery . The battle . Velazco had communicated to Cabañas by letter on January 29 : The Paraguayan forces under Cabañas consisted of a total of 1 , 400 men and 10 artillery pieces . Cabañas directly commanded 1 . 000 men with a division under commander Blas José de Rojas , 200 men from Villarrica with 7 pieces of artillery , an advance force under commander Fulgencio Yegros with two squadrons of cavalry ( urban militias from Villarrica , Villa Real de Concepción and Caazapá ) and five companies of infantry under captain Pedro Juan Caballero , captain Antonio Tomás Yegros , commander García , commander José Mariano Recalde and sub - lieutenant Pedro Pablo Miers . These forces were complemented by 400 men under commander Juan Manuel Gamarra with three pieces of artillery under the command of Pascual Urdapilleta . On the morning of March 7 the Paraguayan troops joined in one place with the arrival of Gamarra ' s forces to the right side of the Tacuary river . Cabañas wrote that day to Velazco : On March 8 a bridge over the river was finished and the Paraguayan troops commenced to cross . On March 9 , the Paraguayans attacked the front of Belgrano ' s position . He was reinforced behind the Tacuarí river , forcing Cabañas ' s forces to cross the river under enemy fire , but Cabañas left only part of his forces to cross directly , including all the artillery , and advanced with the rest through a man - made path through the jungle . Through a path opened specifically for this operation , Cabañas attacked the enemy at their flank . Colonel José Machain moved to the side to repel them , but was surrounded by Paraguayan cavalry and forced to surrender . Therefore Belgrano left only a few men in a defensive position and marched to help Machain . Commanding the defenders was at the river crossing was major Celestino Vidal , who was left almost blind by cannon fire . Belgrano refused to surrender under Cabañas request , and maintained a steady resistance , which forced the Paraguayans to stop their advance . Rapidly , Belgrano retreated with the remainder of his army to a nearby hill . From there he sent a communication to Cabañas , saying Cabañas took that communique as a request for armistice , and ordered Belgrano to abandon the province completely in one day . Consequences . Even though his army suffered a serious defeat , there are some accomplishments by Belgrano from his defense at Tacuarí . In first place , he succeeded in extracting an important part of the army from Paraguay , about 400 men , including the prisoners captured with Machain . These men would form the for the future United Provinces army that would fight at the Banda Oriental ( present - day Uruguay ) , supporting the local militia commanded by José Artigas . Belgrano wrote a proposal that general Cabañas took to Asunción to form the base for a peace treaty between Asunción and Buenos Aires ; this included free commerce between the two capitals and the formation of a new local government in Asunción . He also requested this new government to send a representative that would form part of the Government ( Junta ) in Buenos Aires and would negotiate all the reparations that would be paid by Buenos Aires for the war they took to Paraguay . Belgrano made the condition that this would require at the formation of a local autonomous government ( outside of Spain and the Royalists ) and that it recognized the rebel government in Buenos Aires . His best success , in any case , was to have Paraguay start to seriously consider independence from Spain , even without joining the United Provinces . In effect , shortly after May 14 , the Paraguayans declared their independence from Spain ( on May 17 ) and formed their first government after a peaceful rebellion at Asuncion that forced the resignation of the entire city and provincial councils , after a plan to have Portuguese troops from Brazil as reinforcements to the Spanish troops as counterweight to the Argentine troops was exposed . Among their first proponents were several of the victors at Tacuarí , especially Fulgencio Yegros . Belgrano ' s campaign did not accomplish their goal of having Paraguay to form part of the United Provinces of the Río de la Plata , joined by the other ex - provinces of the Viceroyalty of the Río de la Plata . Due to his military defeat in Paraguay the Primera Junta in Buenos Aires opened a Court Martial for Belgrano on June 6 , 1811 , even though they did not have a definite charge against him , instead a people ' s petition ( " petición del pueblo " ) to make the charges that " would be appropriate " . Nobody presented any charges against him , and the officers under his command in the Paraguay campaign did not have any complaints and defended his patriotism and irreproachable conduct . Finally , the government decided on August 9 , 1811 to absolve him of all charges and published the verdict in the " Buenos Ayres Gazette " The Drummer boy of Tacuarí . There is an Argentine myth about a child called the " Drummer of Tacuarí " who would have been involved in the battle . It is said that it was a 12 years old child , acting as military drummer in the first lines of battle , being guide of the above mentioned commander Celestino Vidal and was playing a snare drum . It is also said that his name was Pedrito Ríos , that he was born in Concepción del Uruguay and that he died in the battle . However , this child is not mentioned in battle reports of the time , either the immediate ones or others made days or months later . The first mention to the drummer of Tacuarí was formulated 45 years after the battle , and depicted shortly after in a portrait with a 50 - years old blind man ( however , Vidal was nearly 21 years old when the battle took place ) . This portrait would be based on many improbable ideas : that the army was led by a blind man ( in real life Vidal was almost blind due to cannon fire ) , that a 12 years old child would be allowed in the front lines , and that a child might be able to serve both as guide of a blind man and a military drummer in the middle of a battle between Argentines and Spanish royalists . This myth has made way into Argentine military history , a legend told through the years . In light of this , today , the " " Tacuari Drummer " " Regimental Band of the 1st Regiment of Foot Infantry " Patricios " has a young snare drummer in its ranks , bringing this story to the 21st century Argentina . This is the only Argentine Military band to have a child play as a military musician , in tribute to the young drummer from Concepcion del Uruguay who used his talent , at the cost of his life , to bring victory to the Argentine forces and would result , indirectly , in Paraguay ' s independence days after , with several of the victorious royalist officers and soldiers supporting it . Bibliography .