On the morning of July 26, 1762, a combined British and Miskito force laid siege to the fortress in what would later be called the Battle for the Río San Juan de Nicaragua. This expedition, which had originally sailed from a base in Jamaica, consisted of seven large boats and several canoes. The garrison commander, Don José de Herrera y Sotomayor, had died unexpectedly 11 days earlier. Inspired by acts of heroism displayed by Herrera's 19-year-old daughter Rafaela (including killing the British commander), "pro tempore" garrison commander Lieutenant Juan de Aguilar y Santa Cruz led the defenders to victory in a battle that lasted six days. The British finally lifted their siege and retreated on August 3, 1762. In 1781, King Charles III of Spain issued a royal decree granting Rafaela Herrera a pension for life, as a reward for her heroic defense during that battle. After Spain entered the American Revolutionary War in 1779, Major General John Dalling, the British governor and commander-in-chief of Jamaica, proposed a second naval expedition to Nicaragua. The goal was to sail up the San Juan River to Lake Nicaragua and capture the town of Granada, which would effectively cut Spanish America in half as well as provide potential access to the Pacific Ocean. During this expedition, which took place in 1780 and later became known as the San Juan Expedition, Colonel John Polson and Captain Horatio Nelson led a British attack against the fortress. At the time, the Spanish garrison consisted of 228 men under the command of Juan de Ayssa (who later served as Governor of Nicaragua from 1783 – 1787). The expeditionary force succeeded in capturing the fortress on April 29, 1780, despite the fact that it consisted of only 200 men. The 22-year-old Nelson, in command of , was responsible for leading his men through dense jungle to attack the fortress from a hill in the rear. The British captured the fortress and occupied it for nine months, finally abandoning it in January 1781. The hill is named "Lomas de Nelson" to this day. The topographic features include hilly soil, with good conditions for agriculture and livestock. The village is situated in a tropical rainforest climate, with wet weather conditions. The average temperature is about 25°C, and annual rainfall ranges from 2,800 to 4,000 mm. From 1948 to 1951 and then from 1968 to 1970, the municipality of El Castillo was a major producer of bananas. The bananas were transported to Puerto Limón in Costa Rica, where they were sold by U.S. companies.