The Jesuit Reductions were a particular version of the general Catholic strategy used in the 17th and 18th centuries of building reductions (reducciones de indios) in order to be able to Christianize the native populations of The Americas more efficiently. They were created by the Catholic order of the Jesuits in the areas inhabited by the Tupi-Guarani peoples, generally in an area corresponding to modern day Paraguay, although later they were extended into the areas that are now Argentina, Brazil, Bolivia and Uruguay. The Jesuit reductions of this area were different from the reductions in other areas in that they did not seek to make the indians adopt a European way of life, but only the Christian religion. Under the Jesuits leadership of the indians which was effectuated through native "puppet" caciques the reductions achieved a high degree of autonomy within the colonial empires. With the use of indian labour the reductions also became economically successful. When their existence was threatened by the incursions of bandeira slavetraders, they even built up militias of indians that fought effectively against the colonists. The resistance of the Jesuit reductions to slaveraids as well as their high degree of autonomy and economic success are often cited as reasons behind the expulsion from the Americas in 1767. The Jesuit reductions are a controversial chapter of the evangelisational history of the Americas and are variously described as socialist jungle utopias or as authoritarian theocratic regimes of terror.
The reductions originated in the early seventeenth century when the Bishop Lizarraga asked for missionaries for Paraguay. In 1609 three Jesuits began the first mission in San Ignacio Guazú. In the next 25 years 15 missions were founded in the province of Guairá. But since some of these were within the Portuguese area they were subjected to frequent destructive raids by Bandeirantes of Sao Paulo in order to enslave the indians. In 1631 then most of the reductions moved west into Uruguay which was under Spanish jurisdiction. The missions also secured the Spanish crowns permission to raise militias of indians in order to defend the reductins against these raids. The bandeirantes followed the reductions into Spanish territory and in 1641 the indian militia stopped them at Mbororé.
At the height of the reductions there were around 40 different communities that were home to as many as 150,000 indians, most of whom were Guaraní, Tupi and Chiquitos. Reductions were laid out according to a standardised cityplan: the main buildings, like the church, college and churchyard were concentrated around a wide square, with houses facing the other three sides. Each village also provided a house for widows, a hospital, and several warehouses. In the centre of the square, there was a cross and a statue of the mission's patron saint. The reductions were ruled by native rulers who served as the reductions governor, but who was in reality under the control of the Jesuit order. The social organisation of the reductions has often been described as extremely efficient and most of them were self-supporting and even produced surplusses of goods that were in turn traded to outside communities. This laid the foundation to the rumours of the Jesuits guarding immense riches required through the indians labour. In reality the communities were economically successful but hardly constituted any important source of income for the Jesuit order.
The reductions came to be seen as a threat by the secular authorities. The economical success of the reductions which was considerable although not as great as it has often been described, combined with the jesuits independence became a cause of fear. When the Jesuits were expelled from the Spanish realm in 1767 the reductions slowly died out, becoming victims of slaveraids or simply absorbed into European society. All that remains today from that period are ruins of some of the Reductions, and two creole languages based on Guaraní, Tupi and Portuguese called Língua Geral and Nheengatu.