Paraguay is among the most Catholic countries in the Americas by identification, and the character of that Catholicism was set by an experiment that lasted a century and a half. Between 1609 and their expulsion in 1767, the Jesuits built some thirty mission towns, the reductions, among the Guarani. They were planned settlements with a church, workshops, schools and communal fields, they operated in the Guarani language rather than in Spanish, and they produced Baroque music, sculpture and printing to a standard that startles visitors to the surviving ruins at Trinidad and Jesus de Tavarangue, now UNESCO sites.
What the reductions were is argued about and always has been. One reading treats them as a refuge: they were fortified against the bandeirante slave raiders from Sao Paulo, and Guarani militias armed and trained in the missions defeated a raiding force in open battle. The other treats them as a total institution: daily life was regulated hour by hour, movement was controlled, and the whole arrangement depended on the authority of the priests. Both readings can be supported from the record, and the expulsion of the Jesuits by the Spanish crown ended the question by ending the missions, after which most of the population dispersed or was absorbed into ordinary colonial labour.
Guarani survived as a national language spoken by most of the population, which is unique in the Americas for a settler majority country.
The pilgrimage to the Virgin of Caacupe each 8 December is the largest annual gathering in the country, with pilgrims walking from Asuncion and beyond.