It was founded in the Roman Era in the upper section of the modern town, in Funtana e Susu, along the road from Usellus to Forum Traiani (Fordongianus), which is marked as Is Romanaius to this day. Siamanna is a small town of about 800 inhabitants, 15 kilometres from Oristano. It sits at the foot of Mount Grighine, which gave its name to the territory extending from the northern borders of Campidano and the historical territories of Barigadu and Upper Marmilla. The town’s name derives from s’ia, meaning ‘the road’, in reference to the Roman road. It was combined with the adjective manna (big), to differentiate it from the nearby, smaller town of Siapiccia, meaning ‘small road’. The two towns were part of the same municipality from 1947 to 1975. Its well-maintained historic centre has characteristic rural Campidanese structure: low houses with large courtyards and narrow roads. The 1512 Parish of Santa Lucia, whose original Pisan Romanesque layout consists of a nave and two lateral aisles, catches the eye in the city centre. In the first half of the 20th century, it fell into ruin and was torn down to be replaced by a new church. Only the 1745 bell tower dating to the Marquisate of Arcais remained standing. Its patron saint is celebrated on August 21 and 22 with two very popular events, the Festival of Su Pannu, brocade or damask cloth once given as a prize at festival race, and the Festival of Typical Products. The festival’s protagonists are Siamannese bread, grapes, cheeses and ricotta, typical of a town of shepherds and farmers cultivating cereals, fruit, olives and grapes. During the festival, the farmers cook ravioli according to traditional recipes for visitors. Religious celebrations are repeated on December 12 and 13 with a bonfire and a procession. On a hill about two kilometres from the town stands the Church of San Giovanni, a must-see. Possibly constructed in the 16th century and restored several times. Its patron saint is celebrated in late June with a dinner, music and traditional dancing. Adjacent to the church stands a nuraghe of the same name, the most important of nine surrounding the town, which predate by several centuries the Punic period and the extensive ‘Romanisation’. The other nuraghes are Auredda, Concu, Crogana, Curreli, Monte Qua Sigu, Paba de Soli, Pajolu, Pitzu Cau and Santa Vittoria.
Mount Grighine is over 700 metres in height and dominates the fertile lands around Siamanna, cut by valleys and crossed by the Mannu River. The mountain is a Palaeozoic island formed 500 million years ago. Its slopes contain outcrops of basaltic and granitic rocks eroded by the wind, alternating with, at times impenetrable, Mediterranean shrubs and ‘flashes’ of century-old holm and cork oaks, at Sa Cora e Is Ottus and Su Sruesciu Nieddu, for example. A refuge for bandits in the past, today, the mountain hosts an imposing wind farm.