Banda Oriental

After decades of disputes over the territories, the 1777 First Treaty of San Ildefonso settled the division between the Spanish Empire and the Portuguese Empire: the southern part was to be held by the Spanish Viceroyalty of the Río de la Plata and the northern territories by the Portuguese Capitania de São Pedro do Rio Grande do Sul (English: Captaincy of Saint Peter of the Southern Río Grande).

During the conquest of the Río de la Plata area by the "Adelantados" (1535–1590), the main concern was to reach the interior in search of precious metals, so this region remained mostly ignored.

[3] In 1542 the Crown of Castile established the Viceroyalty of Peru, a colonial administrative district that originally contained most of Spanish-ruled South America, governed from the capital of Lima.

[4] Later the name was extended to encompass Entre Ríos, to describe the territories in those latitudes that lead to the Mar del Nord (Atlantic Ocean).

The area north of the Banda Oriental was the territory called by the Guaraní word Mbiaza or Ibiazá, rendered in Spanish as La Vera.

Following the recommendation of the King of Spain, Hernandarias introduced a large amount of cattle in the Banda Oriental, an act which has played a decisive role in the future of the economy of the area.

[3] Another notable development came from the reductions of the Compañía de Jesús further north of the Uruguay River, where indigenous Guaraníes and Tapes were being kidnapped from the missions by the bandeirantes to be used as slaves in São Paulo.

[3] Although Spain claimed the territory of the Banda Oriental, based on the Treaty of Tordesillas, it did not officially belong to the Spanish Crown during the 17th century.

The Portuguese, being able to advance without resistance in the sparsely populated territory, founded the city Colonia del Sacramento on the banks of Rio de la Plata, across from Buenos Aires, in 1680.

The following years saw an expansion of the Portuguese settlements around Colonia del Sacramento, until 1723, when Field Marshal Manuel de Freitas da Fonseca of Portugal built the Montevieu fort.

At the conclusion of the Spanish–Portuguese War of 1776-1777, by the First Treaty of San Ildefonso, Spain returned the island of Santa Catarina to Portugal and recognized Rio Grande de São Pedro as Portuguese territory, but kept the Colonia del Sacramento, along with the Banda Oriental, and the Misiones Orientales.

With little help from Buenos Aires, he was sent to organize a rebellion in the Banda Oriental, where Montevideo was now the new capital of the viceroyalty, with Francisco Javier de Elío as the new viceroy.

Fearing defeat, Buenos Aires signed a truce with Elío, recognizing him as the ruler of the Banda Oriental and half of Entre Ríos.