In the past, it played a strategic role in trade with the Sicilian hinterland, since this river is a tributary of the Gibesi, and the Gibesi in turn a tributary of the Salso River, which was once navigable. Excavation campaigns have shown that the site where the castle stands has been inhabited since the third millennium BC. The castle’s structure is articulated into four levels: the first level has a variable height adapted to the morphology of the terrain, with lower elevations to the north. On the eastern side lies the entrance, covered by a pointed barrel vault; the second level corresponds to the floor above the entrance vault; the third level preserves the only covered chamber that has survived to this day, with a pointed-arch vaulted ceiling and five loopholes in the walls, while the last features a crenellated walkway and the remains of the largest tower with four windows facing west.
The castle was the scene of bloody battles that caused fires and partial destruction, from the Norman conquest to its near-total ruin during the War of the Vespers. Among the many stories that marked the life of the Castle of Delia, one became famous through the publication of a literary work known as Historia Sicula and attributed to Nicolò Speciale. This work recounts a tragic episode that took place within the walls of the Castle of Delia. A romanticized version of the Delia chronicle of the Historia Sicula was also produced by the writer Mezzabotta, who enriched the story with many details. While some of these may reflect historical truth, others cannot be verified with certainty.
The castle was rebuilt during the 14th century. There is evidence of the presence of barons from the Ortolano family in the fortress from the 15th century until the first half of the 16th century. From then on, the site went through a period of abandonment, followed by a recovery phase during the major construction works for the foundation of Delia starting in 1598. Definitive abandonment occurred in the 17th century, and by the mid-18th century Vito Amico described it as a ruin. From that time on, the castle became known as the Torre del Castellaccio. At the end of the 19th century, it was declared a national monument and underwent its first restoration, which attributed its origins to the Norman period (Castle of the Normans). The current appearance of the castle is the result of archaeological excavations and restoration campaigns carried out between 1987 and 1995, which restored the ancient fortress to how it looked at the beginning of the 17th century.