On 9 March 1811, on the Tacuarí River in southern Paraguay, Paraguayan troops under Manuel Atanasio Cabañas outflanked and defeated the small army that the revolutionary junta of Buenos Aires had sent under General Manuel Belgrano. Belgrano capitulated and was allowed to leave the province with his men. The campaign failed to bring Paraguay under Buenos Aires, but two months later Paraguayans removed their Spanish governor and set out on their own road to independence.
An expedition to win Paraguay
After the May Revolution of 1810 a junta took power in Buenos Aires. Paraguay, governed by the Spanish official Bernardo de Velasco, did not accept its authority, and in September 1810 the junta gave Manuel Belgrano the task of leading an armed expedition there. The Argentine province of Misiones recalls that his troops crossed the Paraná into Paraguay in December 1810.1
The expedition was small. On 19 January 1811 Paraguayan forces beat it at Paraguarí, near Asunción, and Belgrano fell back south to a defensive position on the Tacuarí River.2
Outflanked at Tacuarí
Cabañas, now commanding the Paraguayans, decided not to attack the position head-on but to envelop it. On 9 March Paraguayan troops appeared on Belgrano's right flank near the hamlet of Tupá-ra'ý. According to the Cuban encyclopedia EcuRed, Belgrano sent Colonel José Ildefonso Machain with 150 men and two guns to stop them; after hand-to-hand fighting Machain's force had to surrender.3
With his flank turned, Belgrano asked for terms. No reliable count of the armies is given in these sources, but all of them describe Belgrano's force as clearly outnumbered and beaten.4
A capitulation between future allies
The terms were generous. The cultural service of the Argentine province of Misiones describes a mutual agreement with no victors or vanquished, in which arms, flags, prisoners and wounded were exchanged and Cabañas escorted Belgrano back to the Paraná with military honors. Belgrano also opened talks and a correspondence with Cabañas and other Paraguayan leaders, using the defeat to argue that Buenos Aires had come to help, not to conquer.5
Not everyone in Paraguay approved. The historian Jerónimo Sann quotes a letter in which Cabañas's second in command, Juan Manuel Gamarra, told Velasco that he had had no part in the terms of the capitulation. The Paraguayan newspaper Última Hora reports that José Gaspar Rodríguez de Francia, later the country's ruler, sharply criticized Cabañas for letting Belgrano go.6
Defeat on the field, success in the end?
Buenos Aires failed to bring Paraguay under its rule. Britannica notes that Belgrano later defeated royalist forces at Tucumán and Salta. In Paraguay the campaign had other effects. Two months after Tacuarí Cabañas took part in the revolt that removed Governor Velasco, and the campaign led, as the province of Misiones puts it, to the declaration of Paraguay's independence.7
Última Hora quotes historians who see the negotiations with Belgrano at Tacuarí, conducted on Paraguay's behalf without waiting for Velasco, as the first act of Paraguayan independence. Cabañas and Gamarra were later pushed aside, and it took two centuries for Paraguay's Senate to move to declare them heroes of independence.8
Note: none of these sources gives a reliable count of the armies, and the text gives no invented figures.
