The name apparently comes from muristenes, an ancient dwellings for worshipers and traders, or from the Catalan word for monastery. It is not by chance that since the end of the 20th century, near the parish church of San Pietro Apostolo, there was a building known as domu de is paras, 'house of the friars'. Monastir is located on the fertile Campidano plain, between two little hills of volcanic origin, Mounts Zara and Olladiri, which break up the flat trend of the countryside through which the Riu Mannu and Riu Flumineddu rivers flow. This municipality has four thousand 500 inhabitants and is situated twenty kilometres from Cagliari. It has an agricultural vocation: citrus fruits, peaches and potatoes are grown all over its territory.