The Religious Establishment in Paraguay.

The first missionary work in Paraguay began in 1580 by two Portuguese Jesuit priests, Thomas Fields and Manuel Ortega. Paraguay was a Spanish province that was scarcely settled in the beginning and the Portuguese were able to begin the first missionary work when the Spanish and Portuguese crowns were united under Phillip II. The two main centers for religious administration were Asuncion and Guayra. It was from these two centers in which Fields and Ortega combed the rivers and jungles of Paraguay to instruct groups of Guarani Indians.

At first, the Guarani were suspicious of the Jesuits and the emissaries they sent out ahead to seek out the caciques but, gradually, by means of small gifts and the "powerful force of the Truth," the Guarani were "moved to abandon their lairs and form towns." (pg 46) These towns were called aldeas which are the primitive precursors to the reducciones that were formed later in Paraguay. The main problem the two missionaries had to contend with was groups of Indians who returned to their primitive ways and habits in the the jungle. Because of the lack of manpower in Paraguay there were no priests able to keep constant contact with the aldeas already formed. By 1590, the crown sent more missionaries to Paraguay to combat this problem which allowed Fields and Ortega to form new aldeas and help return former aldeas to the Catholic doctrine.

In 1590 there was a smallpox epidemic throughout Paraguay which gave the Jesuit priests the oppurtunity to reinforce Catholic dogma concerning sin and retribution. They depicted "God as the Avenger, who punishes the sins by sending plagues upon the land." (pg 47) However, it was the selfless caring for the sick and dying that earned the Jesuit missionaries the affection of the Guarani.

In 1599, the Portuguese abandoned the territories of Paraguay because it was felt that they could not properly meet the needs of the various regions of Paraguay. In 1601, after a letter from Thomas Fields who wanted to salvage his work in Paraguay, Rome issued a decree formally establishing the territory of Paraguay giving jurisdiction to the Spanish Jesuits. By 1605 the Spanish had arrived to formally setup a new Jesuit province in Paraguay.

McGeagh, Robert. "Thomas Fields and the Precursors of the Guaraní Reducciones." Colonial Latin American Historical Review 2, no. 1 (1993): 35-55.