Mission San Cosme y Damian church

The name was given by Jesuits after Saints Cosmas and Damian, twin brothers from third-century who practiced medicine.[1]

The Jesuit ruins found in San Cosme y Damián are the remains of some 30 missions, also known as reductions (Spanish: reducciones), found in the Río de la Plata region. The San Cosme y Damián mission was one of seven missions located in Paraguay; the other missions are found in modern day Argentina and Brazil. The Jesuit mission of San Cosme y Damián was founded in 1632 by Father Adriano Formoso. The settlers had to move several times before ultimately establishing themselves upon the north bank of the Paraná River in 1718.[1][2]

The ruins of the San Cosme y San Damián mission holds several well-preserved artifacts and archaeological finds. These ruins are the only ones in Paraguay to still have a functional church, which has been continually used to this day as a place of worship and as a community centre. The church also has original wood carvings, a number of them even with their original colouring. Some of these carvings depict Jesus with indigenous features. The school and priests' rooms are also well-preserved. One can still observe the original painted ceiling and stone ornaments made by the inhabitants. As of April 2022, there remains a side of the mission that has not been excavated.[2]

During the 18th century, Mission San Cosme y San Damián was also the site of an observatory, due to the work of Father Buenaventura Suárez. Born in Santa Fe, Argentina in 1678, Father Suárez came to San Cosme y Damián in 1703. He stayed and worked there till his death in 1750. With the help of the Guaraní people, he built several astronomical devices such as sundials, telescopes, quadrants, etc. Although rudimentary in nature, these devices were completely functional and accurate and allowed Father Suárez to make many observations. He sent his observations of eclipses, satellites of Jupiter, and the rings of Saturn to European scientists who were intrigued by astronomical data from the Southern Hemisphere. Some of his findings were even published in European journals.[3] Father Suárez's work culminated in the publication of his book Lunario de un Siglo (English: Lunar Centenar) in 1743. This was an astronomical calendar of a century, 1740-1840. This book predicted with great accuracy the eclipses that would occur in this time period and also contained geographical data of 70 cities. Nearly all of his instruments have been lost, with only the sundial still remaining in the schoolyard.[2][4]

Other priests who played an important role in the development of San Cosme y Damián include Fathers Adolfo Scal, Johan Gilde, Unger and Taddaeus Enis. Father Enis was especially famous for leading the native population in battles against the Portuguese.[1]