The Fortress of the Immaculate Conception, (Spanish: El Castillo de la Inmaculada Concepción) is a fortification located on the southern bank of the San Juan River (Río San Juan), in the village of El Castillo in southern Nicaragua. The fortress is situated approximately 6 kilometers from the border with Costa Rica, at the Raudal del Diablo rapids of the San Juan River. It was completed in 1675 as part of a series of fortifications along the San Juan River, to defend against pirate attacks upon the city of Granada (which can be reached by navigating upstream from the Caribbean Sea along the San Juan River into Lake Nicaragua). The settlement of El Castillo and its fortress continued to be strategically important to the Captaincy General of Guatemala until the late 18th century.
An important historic landmark of Nicaragua, the fortress is on a list of sites as an initial stage in achieving World Heritage Site status with the United Nations Educational, Scientific and Cultural Organization (UNESCO).
History
16th century
Gil González Dávila was a Spanish conquistador and the first European to arrive in present-day Nicaragua. After discovering the "freshwater sea" (Lake Nicaragua) on January 21, 1522, he speculated that it discharged into the Caribbean Sea. Francisco Hernández de Córdoba was another Spanish conquistador who founded the city of Granada (the first Spanish colonial city in Central America) on the shore of Lake Nicaragua on December 8, 1524. Under orders from Hernández de Córdoba, an expedition that included Hernando de Soto, Ruy Díaz (the first mayor of Granada) and Sebastián de Belalcázar explored Lake Nicaragua. They succeeded in locating a waterway running eastwards towards the Caribbean Sea, but reported it to be not navigable. Martin Estete, a citizen of Granada, finally discovered the outlet of Lake Nicaragua in 1528 and named it the Río San Juan. Estete was unable to navigate past the rapids however, because the river was low at that time. In 1529, Diego Machuca became the first man to reach the Caribbean Sea from Lake Nicaragua. After circumnavigating the lake in a group of boats, Machuca and his team entered the San Juan River. From here, Machuca led a group of 200 men who advanced by land, taking the same course as the boats. Machuca named the rapids (the rapids which stopped Estete the year before) after himself, and named the port at the mouth of the river San Juan de las Perlas (later known as San Juan del Norte, and now known as San Juan de Nicaragua).
17th century
By the late 17th century, the success of the city of Granada had made it a victim of pirate attacks, the first of which was in 1670 by the pirate Gallardino. In response to this and other pirate attacks, the Spanish colonial authorities constructed the Fortress of the Immaculate Conception as a means to protect the citizens of Granada from future attacks.
Captain General Fernando Francisco de Escobedo, who was also at that time Governor of Yucatán, visited the area from January – February 1673. Escobedo was accompanied by Martín de Andújar Cantos, a military engineer who was responsible for the selection of the site. Escobedo and Andújar Cantos arrived at San Juan del Norte, then travelled upstream along the San Juan River and into Lake Nicaragua. Upon their return to Granada, they set about planning the construction of definitive fortifications along the San Juan River. They ultimately decided to build the fortress at the Raudal del Diablo, (known at that time as the Raudal de Santa Cruz) atop the ruins of the previous Fuerte de Santa Cruz, which dated from the time of King Philip III of Spain. Construction of the fortress, initially named Fortaleza de la Limpia Pura e Inmaculada Concepción, was begun on March 10, 1673, and completed in 1675. Despite the construction of the fortress, buccaneer William Dampier plundered the city and set it on fire on April 8, 1685.