Guaraní War

The Guaraní War (Spanish: Guerra Guaranítica, Portuguese: Guerra Guaranítica) of 1756, also called the War of the Seven Reductions, took place between the Guaraní tribes of seven Jesuit Missions and joint Spanish-Portuguese forces. It was a result of the 1750 Treaty of Madrid, which set a line of demarcation between Spanish and Portuguese colonial territory in South America.

The boundary drawn up between the two nations was the Uruguay River, with Portugal possessing the land east of the river. The seven Jesuit missions east of the Uruguay River, known as the Misiones Orientales, were to be dismantled and relocated on the Spanish western side of the river. The seven missions were called San Miguel, Santo Ángel, San Lorenzo Martir, San Nicolás, San Juan Bautista, San Luis Gonzaga, and San Francisco de Borja. These missions were some of the most populous in South America with 26,362 inhabitants, according to a Jesuit census, and many more in the surrounding areas.

In 1754 the Jesuits surrendered control of the missions, but the Guaraní peoples, led by Sepé Tiaraju, refused to comply with the order to relocate. Efforts by the Spanish army in 1754 to forcefully remove the Guaraní from the missions failed. On 10 February 1756, a combined force of 3,000 Spanish and Portuguese soldiers fought the Guaraní at the battle of Caiboaté. It resulted in the death of 1,511 Guaraní, while the Europeans suffered only 4 deaths. In the aftermath of the battle, the joint Spanish-Portuguese army occupied the seven missions.

Eventually, Spain and Portugal annulled the 1750 treaty in the Treaty of El Pardo (1761), with Spain regaining control over the seven missions and its surrounding territory.