Paraguay: Colonial Period

Spanish expeditions searching for a route to Andean silver reached the Paraguay River in the 1530s, and in 1537 Domingo Martínez de Irala's men established a fort at Asunción that became the base for Spain's colonization of the region. Finding little gold, the settlers instead built close ties with the Guaraní, intermarrying extensively; the resulting mixed population shaped the colony's language and customs for centuries. From Asunción, Irala extended Spanish authority east toward the Paraná River and organized the surrounding territory, while a line of frontier forts checked Portuguese expansion from Brazil.

For much of the 17th and 18th centuries, Jesuit missionaries administered a network of some thirty reducciones in the Paraná and Uruguay river basins, communities that combined religious conversion with agriculture, craft production, and defense against slave raiders from São Paulo. These missions operated with unusual autonomy from colonial authorities in Asunción, prompting resentment among Spanish landowners who wanted access to Guaraní labor. That friction, combined with wider Bourbon reforms, led the Spanish crown to expel the Jesuits from its territories in 1767, after which the mission settlements were abandoned and fell into ruin.

The colony's status shifted again in 1776, when Spain created the Viceroyalty of the Río de la Plata and placed Asunción under the authority of the new viceregal capital at Buenos Aires. The change diminished the region's earlier importance as a hub of Spanish power and deepened local resentment of Buenos Aires's control, grievances that would surface a few decades later as Paraguayans began pressing their own claims to self-government.