Jesuit Mission of San Cosme y San Damián

Date of Submission: 06/04/2022
Criteria: (iv)
Category: Cultural
Submitted by:
Permanent Delegation of Paraguay to UNESCO
State, Province or Region:
Department Itapúa, City San Cosme y San Damián
Coordinates: S27 19 13.44 W56 19 58.08
Ref.: 6613

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The Jesuit Mission of San Cosme y San Damián is one of a group of 30 Jesuit missions in the Rio de la Plata Basin and one of the seven remaining Jesuit missions in Paraguay. The current municipality of San Cosme y San Damián has an approximate population of 10,000 inhabitants and a surface area of 800 km², and is situated along the Paraná River coast. This Tentative List submission is for the extension of a serial property already inscribed in the UNESCO World Heritage List in 1993: The Guaraní Jesuit Missions of Santísima Trinidad del Paraná and Jesús de Tavarangüe of Paraguay.

During the 17th and 18th centuries, the Catholic religious order of the Society of Jesus (Jesuits) established an assemblage of 30 missions, also known as reductions, in the Río de la Plata Basin within territories belonging to the Río de la Plata Governorate of the Spanish Empire and the indigenous Guaraní peoples. These 30 Guaraní Jesuit reductions were located along and near two of the most important rivers of the Rio de la Plata Basin: the Paraná and Uruguay Rivers and in the tropical jungle of the Atlantic Forest within present-day Paraguay, Argentina and Brazil.

The Jesuits arrived in the Guairá region of Paraguay in 1588 with the permission of King Felipe II of Spain to implement their objectives of Christianizing the indigenous population and saving them from the Spanish encomienda, the colonial labor system with slave-like conditions. The Jesuits gathered members of the indigenous population and encouraged them to adopt a sedentary way of life while practicing the Christian religion, but unlike other Spanish missions in the New World, the natives were not forced to fully "Europeanize." Many indigenous traditions were preserved, encouraged and carried out by the Jesuits alongside the indigenous Guaranies, such as the cultivation of yerba mate (Ilex paraguariensis), a plant used in a traditional tea that is still consumed by 90% of the current population of Paraguay. Also practiced was the belief in the search of the Land Without Evil was also implemented by the Guaranies. It is the fundamental belief that a cataclysm will destroy the world and the Guaranis will find salvation in a harmonious paradise. These traditional Guarani practices in religion, language, and political systems were combined with the Jesuits’ worldview of Catholicism and European society. With this unification, the reductions represented a true cultural experiment that has not be truly duplicated in other parts of history. The Guarani had protection under the laws of the Spanish Crown and the financial support from the Jesuits in the form of goods, housing and services. The Jesuits accepted indigenous institutions and practices because they considered the chief of the tribe the corregidor, or mayor, who was the highest authority in the mission.

Although the Spanish Crown was technically the highest political authority, the indigenous Guarani were much more autonomous in the reductions compared to the encomienda style; many held important political roles and were involved in decision making. Each village had a council, cabildo, elected yearly for consideration by the priests and then confirmation by the governor. The priests had more of an administrator-like role in the reductions, yet they held the power of direct intervention in all aspects of daily life including religion, military, education, and economics.

Regarding the economic organization of the reductions, each village was managed as an independent economic unit with a barter system, as there was no local currency at the time. The Jesuit fathers implemented an agricultural economic system focused on livestock, particularly cattle. However, the traditional indigenous extraction of natural resources such as yerba mate was also critical to economic trade. Yerba was exported as far as Chile and Potosí for making the traditional Paraguayan tea. There was intense commercial traffic between the reductions as well, promoting the economic, social and political integration of more than 200,000 people.

The property of the missions was both privately and communally owned. Private land was not that common amongst indigenous residents; however, some Guarani community leaders were awarded their own land, something unheard of in other parts of colonial Latin America at that time. Many of the goods were shared, like food, clothes and housing which kept costs down and provided necessities to all residents of the reductions. Due to the nature of the reductions, some have called them an experiment in "socialist theocracy" or a rare example of "benign colonialism".

In education, primary schools for children operated in all the reductions. The Jesuits taught Spanish to achieve linguistic unity amongst the two groups, yet they also spoke fluent Guaraní, using the language as a tool to understand the natives. Other classes included painting, sculpting, and music, which was prominent in the villages. Each reduction had a choir and orchestra and during performances, the Guarani used instruments such as the harp and the violin made by themselves in the workshops.

The missions’ original urban designs were generally similar in all reductions with a few exceptions. However, without fault, the church was always in the center of the towns in a square oriented according to the four cardinal points, with crosses or statues and sanctuaries in the four corners, to represent the importance of religion. Each church was ornately decorated and had a high bell tower with which mass was called or an occasional general meeting. All streets within the town led to the central church. Next to the church was the residence of the Fathers, with the houses of the indigenous chiefs, or caciques, nearby. The rest of the mission consisted of indigenous housing, the patio, workshop cloisters, garden, orchard, cemetery, and the jail. The streets were approximately 16 to 18 meters wide and were arranged in a radial form starting from the central square. The houses of the indigenous residents were approximately 60 square meters, made of bricks and supported with arcaded walls. The urban centers were surrounded by farms and a road network that connected to other populated centers and missions.

After building the missions and their urban centers, the reductions began to fortify themselves by forming militias. The indigenous militias combined training in modern warfare tactics of veterans of the European wars with their traditional jungle tactics. The Guarani missions’ militias constituted a very important stop on the expansionist aspirations of the Lusitanians, who were dedicated to hunting the Guaraní to sell them as slaves in Brazil. The Guarani militiamen also participated in numerous campaigns against other groups such as the Guaycurúes, Payaguás and Mbyás, aggressive tribes of the Gran Chaco that frequently launched attacks on towns in Paraguay. This demonstration of the military power of the missions impressed and intimidated the residents of Asunción and Corrientes, who had built mistrust in the missions during that time.

 A few decades after forming the militias, the Guarani War took place between the Portuguese and the Guaraní. This war was eventually used as the main argument to expel the Jesuits from the region since they were no longer considered loyal to the Crown. The expulsion of the Jesuits and later degradation of the missions negatively affected the regional economy, demonstrating the missions’ importance economically. As for the Guarani, some stayed in the missions, some returned to the jungle, and others emigrated to Buenos Aires where they used the training as artisans that they had learned in the reductions.

The Jesuit Mission of San Cosme y San Damián was founded in 1632 by Father Adriano Formoso. This reduction is perhaps the one that underwent the most changes; its inhabitants had to move four times until in 1718 when it reached its final home north of the Paraná River. Unlike the remains of the other Jesuit missions in Paraguay, Mission San Cosme y San Damián has functional church, which was restored upon request of the local community. It is still used by residents for religious worship and as a community center. The church has 22 original sacred images carved in wood, some with their original polychrome. The subjects in some of the paintings are striking, such as an image of Christ with indigenous features, demonstrating their importance in the mission. San Cosme and San Damián is also the only mission that still preserves the priests’ rooms with its roof, a two-story structure with the original painted ceiling as well as other attributes that make it unique, which delimit the courtyard corresponding to the cloister of workshops. The rooms or halls of the school maintain niches with the original paintings and carved stone ornaments based on natural and baptismal elements that represent Jesuit teaching and virtues. One side of the mission has still not been archaeologically excavated; therefore, a formal protection of the site is imperative.

Perhaps more interestingly, San Cosme and San Damian was an important astronomical observatory during the 1700s.  Father Buenaventura Suárez, a scientist and geographer, arrived at the mission in 1703 and began his work in astronomy. Assisted by the Guaraní, he built various telescopes, a pendulum clock, an astronomical dial, and a sundial that, although rudimentary, were all accurate in operation. The sundial is still functional today and remains in the schoolyard. Father Suárez built his tools with natural elements from the surrounding environment like reeds, wood, metals and rock crystals. His first telescope consisted of a metal tube on a wooden frame supported by harnesses and pulleys and equipped with two convex lenses. He documented everything he saw, like eclipses of the Sun and Moon, the satellites of Jupiter, and the rings of Saturn, sending his notes back to Europe and arousing the interest of European scientists with astronomical information from the Southern Hemisphere. The result of these observations were his calendars, his celestial maps and his famous Lunar Centenar of more than 200 pages, written in 1720. This study determined the exact dates of the eclipses to take place between 1740 and 1840, detailing the movements of the sun and Earth with astonishing precision. Buenaventura also created accurate maps of the area with all 30 Jesuit missions, globes of the world, accurate weather forecasts, metal bells for the mission, and an herbarium, classifying the various plant species in the region. His work at the reduction alongside his Guaraní assistants added extreme value to fields of science and technology.

Justification of Outstanding Universal Value

The Jesuit missions of the Rio de la Plata region are outstanding representations of a distinct social situation in which two very different cultures mixed and worked together in a way that still affects modern-day ideologies in the region. Their unique urban schemes combined indigenous elements with Christian aspects through symbolism that exhibited Baroque, Romanesque, and Greek influences, as part of an unprecedented acculturation process. The mission of San Cosme y San Damián is exceptional amongst the group because it is still a functional place in the community, serving as a church, community center, and astronomy center with interactive exhibits. The parish church was solemnly consecrated in March 1978, since then mass has taken place regularly. Its well-kept structure allows visitors to learn and interact with a place that is an important part of the region’s history.

The inclusion of San Cosme y San Damián as a World Heritage Site would complement the other UNESCO sites of the missions of Trinidad and Jesus, showcasing the variety in architecture and use of Jesuit missions in the region. This grouping would demonstrate that the missions were connected economically and politically through a network that become the most successful economically in the colonial Americas. With all things considered, it is one of the most important cultural, historical, and religious heritage sites in the country.

Criterion (iv): The Jesuit Mission of San Cosme y San Damián is an exceptional example of the Jesuit missions built in the 17th and 18th centuries throughout this region. The archaeological ruins of this entire urban complex represent a fusion of cultures in which the Christianization process allowed the indigenous population to maintain elements of their traditional culture.

Statements of authenticity and/or integrity


The property contains the buildings of the original complex including: the church, the priests’ dwellings, school building, the gardens and the orchards. The site survived the Guaraní War which then led to the expulsion of the Jesuits in the 18th century. The delimitation of the proposed area includes all the necessary components to express outstanding universal value and the complex is not threatened in terms of adverse development. The complex is highly recognized and appreciated for its cultural values and its role in the cultural identity of the town, both by local and national authorities. A conservation plan to repair and upkeep the architectural integrity is foreseen.


The architecture of San Cosme y San Damián is sufficiently preserved in authenticity of form and design, which is visible in the arrangement of the buildings. It maintains the characteristic elements of a Jesuit mission: the church with galleries, the wooden bell tower, the cloister with the Jesuits’ houses, the school, workshops, and art. The layout corresponds to the urban-sacred space which was implemented in other Guaraní Jesuit Missions. The mission has undergone some renovations since its construction (1988), however all restorations used original materials that had degraded on-site. The renovations have not affected its identifying characteristics or the original architectural pattern. A part of the mission has not even been studied archaeologically.  

What makes this site unique among all the Jesuit Guaraní complexes is the continuity over time of the functions of both the church and the school classrooms. The church building has maintained over the years its original function of worship in the local imagination. It is the only one of the 30 Jesuit Guarani towns that maintains intact its liturgical use and spatial respect of its inhabitants, participating as part of its social structure. The church of San Cosme and San Damián and the classrooms of the school are still used by the local community, the latter for catechism classes or others. The parish church was solemnly consecrated in March 1978, and since then religious ceremony has been celebrated there regularly.

Comparison with other similar properties

In Paraguay, there are two missions, Santísima Trinidad del Paraná and Jesús de Tavarangué, that have been declared collectively as a UNESCO World Heritage Site (1993). They were inscribed on the World Heritage List under Criterion (iv). The Mission of Santísima Trinidad del Paraná stands as the best-preserved urban complex amongst the group. Although it was established in 1706, later than many of the Guarani Jesuit towns, it was the most ambitious of the missions, with a complex covering an area of approximately eight hectares. The mission of Jesús de Tavarangué was never finished before the Jesuits left, however it was still an important site. Today, these two missions are a popular tourist destination in the country, each have their own buffer on the properties, and are located about 100 kilometers away from San Cosme y Damián.

In addition to the Paraguayan reductions, other Jesuit missions in the region have been declared as World Heritage Sites: San Miguel de las Misiones (1983) in Brazil and the missions of San Ignacio Miní, Nuestra Señora de Santa Ana, Nuestra Señora of Loreto and Santa María la Mayor (1984) in Argentina. In the Moxos and Chiquitos areas of Boliva, six Jesuit missions founded between 1696 and 1760 were declared collectively as a World Heritage Site by UNESCO in 1990 (San Francisco Javier, Concepción, Santa Ana, San Miguel, San Rafael and San José).

The construction technique of the buildings of these six Bolivian reductions, unlike that of ​​the Guaraní Jesuit villages in Paraguay, used a wooden bearing with enclosures of non-bearing walls of adobe. The six missions all have profuse religious decoration both on the outside and inside the temples, murals, and decorative elements in carved and polychrome wood. Despite all the decoration, the churches of the missions were eminently simple buildings, composed of a large gabled tile roof, gently sloping, supported by wooden posts. The first mission founded in Chiquitos, San Francisco Xavier, was founded in 1699, and the last were founded shortly before the expulsion of the Jesuits. The Bolivian missions did not be therefore, are much later than the missions of Paraguay, which began to be installed in 1609. The mission of San Jose is the only one apart from San Cosme y Damián that holds both a functional school and church.

Córdoba, Argentina is the religious-administrative headquarters of the Jesuit Province of Paraguay and the Jesuit Block and Estancias of Cordobá (Manzana Jesuítica y Estancias de Córdoba) were named a World Heritage Site in 2000. The Manzana Jesuítica contains the University of Córdoba, the church, the residence of the Jesuit fathers and the Montserrat School. This block along with and the five Jesuit estancias in the Cordoba mountains, which were former agricultural establishments designed and managed by the Jesuit Fathers, are still standing and in use today. The Jesuit estancias in Córdoba are a unique example of the organization productivity of the Jesuits. Each ranch has its own church and set of buildings, around which the cities grew. Although history showed that the rooms were acquired for economic purposes for the maintenance of schools and other study houses, as is logical "they also participated in a certain missionary sense, becoming centers of religious radiation.”