The 17th Century
In the early 17th century, the residents of Asunción del Paraguay, which was the most stable and prospering city in the wider area, spoke of the Banda Oriental or the Stripe of the Charrúas (latter the name was also applied to 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, which was rendered in Spanish as La Vera.
In 1618, during the governance of Hernando Arias de Saavedra (commonly known as Hernandarias), the Banda Oriental was integrated into the Government of the Río de la Plata. 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. Starting around 1626, fathers of the Franciscan order attempted to establish reductions south of Río Negro. Some of them were short-lived missions like the San Francisco de los Olivares de los Charrúas, the San Antonio de los Chanáes and the San Juan de Céspedes. In contrast, the one of Santo Domingo Soriano, founded with Charrúas and Chanáes in Entre Ríos, Argentina, in 1664, was moved on the Isle of Vizcaíno, on the mouth of Río Negro and then in 1718 it was moved again at its present location in the modern Soriano Department.
Another notable development came from the reductions of the Compañía de Jesús further north the Uruguay River, where indigenous Guaraníes and Tapes were being kidnapped from the missions by the bandeirantes to be used as slaves in the coffee plantations of São Paulo. To prevent this, in 1631, father Antonio Ruiz de Montoya migrated with 12,000 Guaraníes further east, in the modern State of Paraná of Brazil, while in 1636, father Nicolás del Techo migrated with another 12,000 Tapes towards the modern Rio Grande do Sul, which constituted the north part of the Banda Oriental of the times.
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. Apart from being seen as an evidence that the Portuguese intended to occupy all of the territory, this port in the mouth of the Uruguay River also permitted the Portuguese ships to carry out illegal trade evading Spanish taxation. Spain took the city twice, in 1681 and in 1705, but had to give it back by the Treaty of Utrecht of 1713.
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