The village of Casciano, sometimes also called Cassiano, is mentioned for the first time in 1189 in a document of Pope Clement III that confirms to Bono, bishop of Siena, the jurisdiction of some churches of the territory. The town was also known by the name of "Casciano delle belle donne" (Village of beautiful women), and this name goes back to the thirteenth century, when shortly after 1252 moved to Casciano a convent of novices.
Casciano was one of the six communities in which the feud of Murlo was divided.
In 1833 the village of Casciano had 634 inhabitants.