The Castle of Poggio Diana, in the territory of the municipality of Ribera, occupies almost the entire narrow and elongated summit of a hill with steep and difficult to access walls, which rises on the left bank of the Verdura river. In its current form, the building is the result of several interventions and restorations that have occurred over time, probably starting from about the mid-thirteenth century. It is in fact from 1356 that the Misilcassim tower begins to be mentioned by the sources, which we can certainly identify with our site; the tower was perhaps built by the noble Chiaromonte family, which has controlled the fiefdom since 1348. Beheaded in 1392 Andrea Chiaromonte and confiscated the assets of the powerful rebel family to the Crown, the fiefdom and the tower of Misilcassim were given to the Peralta family, who held them until 1398, when they were sold to the Perapertusa. in these years the construction of the oldest rooms of the Castle probably arises: Guglielmo receives in 1392 turrim Misilcassimi et feudum; he sold the barony Misilcassimi cum castro to Adelicia, widow of Nicolò Buondelmonte and wife of Bernardo Berengario de Perapertusa in 1398. Between the end of the century and the beginning of the next one seems to have also the first stable presence in the place: with what function it is difficult to say at the moment, but the type of materials found during the excavations that were carried out on the site seem to be indicators of a decent social level. During the restorations carried out during the years 2005/2006, some archaeological tests were in fact carried out, and in particular the fillings of two cisterns were excavated, one used as a kitchen drain, the other instead filled with the materials resulting from a arrangement of the area in front of the building. The ceramics recovered in the two fillings can be dated between the end of the fourteenth century and the first decades of the fifteenth century and present a considerable variety of forms and functional use, as well as peculiar technical and decorative characteristics. Among other things, a significant group of bowls produced by the contemporary furnaces of Sciacca is recognized, as well as some containers of a production so far little known in Sicily, which could be attributed to the same center or to different workshops, located in the western part. of the island. We are in the years in which the castle gravitates into the orbit of the Peralta family, who have their center in Sciacca, where, in the same years, the new castle was built. The construction of the castle of Misilcassim and the presence, inside it, of a stable and numerically consistent nucleus could be connected with the political events of those years, which saw the extreme rebellion against the Crown of Aragon of the exponents of the main noble families, including which Guglielmo Peralta plays an important role. It is in this context, in fact, that the construction of the building can be explained which, due to its position, is strategic for the control of traffic to and from the hinterland.
After Andrea Chiaromonte was beheaded in 1392 and the properties of the powerful family that had rebelled against the Crown were confiscated, the feud and the tower of Misilcassim were enfeoffed to the Peralta family, who held them until 1398, when they were sold to the Perapertusa family. turrim Misilcassimi et feudumIn 1398, he sold the barony to Adelicia, widow of Nicolò Buondelmonte and wife of Bernardo Berengario de Perapertusa Misilcassimi cum castro. Between the end of the century and the beginning of the next, there seems to be the first permanent presence on the site: with what function it is difficult to say at the moment, but the type of materials found during the excavations carried out on the site seem to indicate a fairly high social level.