Soon after the early stages of the conquest of South America, the governments of Spain and Portugal originated the missionary project, whereby religious orders had the task of furthering the development and integration of indigenous peoples. In the sixteenth century, conflicts arose between Portuguese colonisers and the Jesuit missions established between the Paraná and Uruguay rivers. Often violent, these conflicts led to a move of the missions to the Tape region on the left bank of the Uruguay river, in what is now the state of Rio Grande do Sul, in the years following the end of the seventeenth century.
The “Theocratic State of the Jesuits”, embracing 30 tribes, was granted a charter by the Spanish crown and was governed by its own rules of justice, administration and relations with neighbouring peoples. The settlements, seven of which are today situated in Brazil, eight in Paraguay and fifteen in Argentina, had an autonomous system of territorial organization and strict principles for urban development on a linear pattern. Architecture reached a golden phase in its development between 1735 and 1750, when Spain and Portugal defined new territorial boundaries for their colonies in the Treaty of Madrid. After this period, the missionary project entered into a long decline.
The central rectangular square of a settlement contained the church, the college of the Jesuit fathers and various outbuildings on one side, and the houses of the Indian families on the other. The houses, built in rows, had large verandas. The buildings were constructed largely of stone and wood, and have not resisted the attacks of time and periodic fires. A large part of the architectural heritage of the missions has been lost, but important archaeological sites remain today, including the foundations and massive sections of gritstone masonry, and a rich store of objects and utensils.
Listed by Unesco as a World Heritage Site, the ruins of the mother church of São Miguel are the main symbol in Brazil of the missionary civilisation. Designed by the Jesuit priest and architect João Batista Promoli, the church is an example of the baroque architecture of the missionaries, inspired by Renaissance rules established by Vignola for the Gesu church in Rome. The largest piece of religious architecture in the Jesuit settlements, it still possesses the remains of walls, partitions, vaults, facade and bell tower, and, as an important world heritage site, has been preserved and restored by the Ministry of Culture. Next to it is the Museum of Missões, where objects of art and architecture are on display and there is a reconstruction of the settlement and the Indian houses by the architect Lucio Costa.