The origins of Castelvetrano date back to the ancient Sican population of Legum and then to the colonies of so called veterans of Selinunte who were destined to take custody of the victuals (this gives origin to the name of the town "castrum veteranorum"). The existance of this town has only been documented since the Angevins domain. In 1299 Castelvetrano became the property of the Tagliavia family who were to be the future princes of the city, their surname would change to Aragon, then Pignatelli, between the end of the XV century and the beginning of the XVI. Castelvetrano became the capital of the Tagliavia-Aragon territories, enhancing itself with various works of art.

In 1522 Charles V raised the city to county; in 1564 Philip II named it a principality. In the 1600 it was struck by the plague and famine, but in the 1700 it recovered. A visit to the Old Town is an absolute must, both from an artistic and urban point of view. Three ajoining squares (Garibaldi, Umberto I and Principe di Piedimonte), constitute the nucleous that set off the urban development. In a tree-lined airy space, piazza Garibaldi, rises Palazzo Pignatelli - built in the XIII century - and the octagonal tower, the only one remaining of the original four; not far off is the church of Purgatorio, built in 1642 on the remains of the old sacred structure. Another flower in the button-hole of the local 

monumental patrimony is the church of Saint Domenic,in piazza Regina Margherita. It was built by Giovanni Tagliavia in 1470, and Charles of Aragon had it decorated in the 1500s; next to it is the Convent with its beautiful cloisters which have been recently restored. The planimetry of the town highlights a peculiar aspect: about 160 courtyards have been counted, which, being positioned along the road manifests a certain oriental influence due to Arab invasions. The Church of the Trinità di Delia, three kilometres from Castelvetrano is well-worth visiting. It is an Arab-Norman structure dating back to the twelfth century. The hamlet of Marinella di Selinunte is a tourist destination on the sea bordering the archaeological site and the other one in the area is Triscina di Selinunte.