The municipality of Monteriggioni retains many vestiges from the past, bearing witness to the fact that it has been inhabited at least since the eighth century BC, as evidenced by the settlement discovered at Campassini as well as the extensive Casone Etruscan necropolis. The main draws are represented by the castle of Monteriggioni and by the nearby Abbadia Isola, but the whole area is dotted with castles, churches, villas and small villages, surrounded by beautiful unspoilt countryside. Monteriggioni perches on the top of a gentle hill whose slopes are planted with vines and olive trees. The castle was founded in the second decade of the thirteenth century by the Republic of Siena, with the main aim of creating a defensive outpost against its chief rival, Florence. Its military function dwindled after the mid-sixteenth century, when the entire state of Siena was annexed to the Florentine state. Monteriggioni still retains most of the structures of the thirteenth century and is absolutely unique in the panorama of medieval Tuscan villages and towns. Its town walls, which are roundish in shape, encompass the top of the hill and run for approximately 570 meters; the town also boasts fourteen massive towers protruding from the outer surface of the walls. The small town inside the walls was built around a large rectangular square, overlooked by the church of S. Maria Assunta. This is definitely the medieval building which is best preserved, though the entire village, with its characterful narrow streets, boasts many houses which clearly date back to medieval times.