The town came into being during the Middle Ages at the feet of a castle as the groups of structures around it, sas plassas, came together to form a village. Las Plassas is one of the island’s smallest villages, with only 250 inhabitants. It rises in the fertile valley of the Flumini Mannu, its characteristic low houses graced with expansive courtyards nestled around the parish church of San Sebastiano, the patron saint whose feast day is celebrated in January with a huge bonfire. The church dates to the middle of the XVII century and has since been renovated. The town’s main church is Santa Maria Maddalena, a renaissance building constructed at the feet of the castle between the XVII and XVIII century over the ruins of a Byzantine structure. It had a Greek cross floor plan that was then changed into a Latin cross. The octagonal dome and bell-gable with a XVI century bell are all that remain of the original structure. On the outskirts is Santa Maria di Monserrato (late XIV century), home to a Nuragic Age sacred well. It was built in an historically frequented area, nearby is a Punic-Roman oven. Three cross arches divide the hall into four sections. The most heartfelt celebrations here take place on 8 September, while a yearly legume festival is held in late September.
The first outpost of the Arborea Guidicato, Las Plassas became the seat of the powerful Aragonese family, Zapata, its liege, who lived there until the late XX century. An example of the flourishing economy of the Middle Ages, the remains of the Marmilla Castle (or Castello di Las Plassas) are among Sardinia’s most picturesque, isolated on a lone and perfectly conical hilltop that looks out over the plains below. Built in the XII century, it was of military importance, the fortress of the Arborea Guidicato and a mainstay in the war against the Crown of Aragon, under which it fell after the sa Batalla at Sanluri (1409). Some of its rooms served as prison cells until the 1800s. The main tower, walls, perimeters and interior can still be seen today, as can the large well hewn into the rock. The connections between the rooms are worth noting. During archaeological digs some of the furniture, ceramics (XII-XVI centuries) and other relics were discovered, now on display at the MudA museum, located in an XVIII century residence. A multi-media route ends with a film about the visit to the castle by Mariano IV, the ruler, and will take you into medieval Sardinia. A part of the museum is archaeological. Of interest is an epigraph from the 1st century CE, when the local Uneritani population dedicated a temple to Jove. The village was then part of a Uselis colony. Many Nuragic monuments were reused in the Punic-Roman era. The most important of them are the single towered Perdedu and Bruncu e Forru, the five-lobed s’Uraxi and the XIX century BCE giant tomb of Mesedas. The area has been populated since the Neolithic Age, as proven by the Pranu Sonàllas site.