The indigenousGuaraní had been living in eastern Paraguay for at least a millennium before the arrival of the Spanish. Western Paraguay, the Gran Chaco, was inhabited by nomads of whom the Guaycuru peoples were the most prominent.
Paraguay campaign (1810-1811): A militia, commanded by Manuel Belgrano, made its way up to the Intendency of Paraguay. The first battle was fought in Campichuelo and the Argentines claimed victory. However, they were completely vanquished in the subsequent battles of Paraguarí and Tacuarí. This campaign ended in a military failure, but Paraguay broke its links with the Spanish crown just two months after Belgrano's withdrawal.