The Council dictated many regulations and principles, centered on the evangelization of the aboriginals and their fair treatment "not like slaves but as free men", as well as their education and instruction in European customs.
This catechism was later translated into the Guaraní language by Luis de Bolaños, and adopted by the First Synod of Asunción (1603) for use in the area of the Upper Paraná River basin (eastern Brazil, Paraguay and northeastern Argentina).
It set standards for the ordination of priests, requiring that they visit their congregations regularly, and for the appropriate use of liturgy to attract the natives to the celebrations.
The Council adopted a strongly anti-idolatrous tone,[1] targeting obscene books in bishops' possessions for destruction.
[2][a] The Council also ordered the complete destruction of quipu concerning non-Christian customs,[b][4][5] while encouraging their manufacture for confessions[6][c] and doctrinal memorization among the indigenous.