The town of San Calixto, about 17 km from Hornachuelos, is located in the heart of the Natural Park. Its origin is found in the ancient and legendary Monastery of Tardón, founded in the 16th century. XVI by Brother Mateo de la Fuente, disciple of Saint John of Ávila and hermit from the wilderness of Córdoba, in the company of Brother Diego Vidal. Due to their reputation for holiness, many others joined them. Installed in some mountains heavily populated with thistles, which is why they called it Cardón, in a hut that served as their church, they placed an image of Saint Michael. Over time, these anchorites decided to live under one of the rules approved by the church, and chose that of San Basilio, founding in 1543 the Monastery of San Basilio del Tardón, a nickname derived from Cardón, which remained inhabited by monks until the year 1808. Twenty years later, Francisco Sánchez Gadeo founded the last of the New Towns of Sierra Morena, protected by the repopulating spirit of Carlos III and following his colonizing precepts. In memory of the day of the birth of King Ferdinand VII, October 14, the name of San Calixto was given to the new town.