The structure was originated from the pentagonal tower, which leads to think that this fortified complex was built to control the Aventino and Sangro valleys between the end of the 11th century and the beginning of the 12th century. The current castle dates back to the Renaissance. Its history is intertwined with the history of the fief of Casoli, which belonged to the Manoppello County at first (12th century) and then – from 1369 to 1489 – to the Orsini family and finally to the Masciantonio family. The building features a quadrangular internal courtyard and windows that make it look more like a noble palace rather than a defence stronghold. In 1928, the ducal palace and the tower were declared national monuments. A wing of the castle features wall writings by Gabriele D’Annunzio, who lived here.