San Casciano dei Bagni has seen a continuous frequentation by its spa centre that already at the time of Etruscan people was well known. The Roman people succeeded them and though they saw main cities of Etruria land falling down such as the near Chiusi they maintained that place among their favourite ones in the whole Empire. The particular geographic position of San Casciano that place it along the main road that from Northern Italy leads to Roma, in the past ages has caused its development and got it reachable by those who trusted healing properties of its waters. Formerly the San Casciano area was touched at East by the route of Cassia way, one of the most important main roads in the Roman world, and that caused the presence of many famous characters, particularly of Imperial Rome. The Romans, the real appreciators of spa, leant on the healing properties of those waters. The frequentation of many Roman citizens by those sources is witnessed by the several tombstones the for ages have been cropping out in the countryside around San Casciano and among them the Triaria's one is the highest, the Vitellio Emperor's wife. Even Ottaviano Augusto healed himself in those sources according to what you can realize by Orazio's and other Classical authors' works. The force of this centre is witnessed even by the precocious penetration in Christianism, already in 4th and 5th century in San Casciano there was a Parish church voted to Saint Mary in Balneo (in bath). The barbarian invasions and the struggles between Longobardian and Bizantyne reduced the importance of San Casciano, provoking a remarkable reduction of population. That's the period when you get the first written pieces of news about San Casciano: in 995 when the marquis Ugo from Toscana gave the “Curtis (de) Bagno” to the Saint Salvatore Abbey. Once more the closeness to a great road was the development and promotion source of San Casciano Spa, in fact the Cassia way had lost its importance during the wars between Bizantyne and Longobardian who faced the ones against the others; in the Perugia area the Bizantyne of exarchate, in Siena area the Longobardian, and the latter ones definitely moved the ancient Consular way to the inner side of their lands. Thus the Francigena way was instituted and it passed a few km west far from San Casciano dei Bagni. Nearly at the end of 18th century San Casciano start a progressive decadence due to the crisis of spa, not succeeding in adaptin to the new standards of the domain. The 19th century opens to the intense Napoleonic eve further to the incorporation of Toscana region in the Napoleon's French Empire, thus the Restoration period, by the return under the granduchy of Toscana and eventually, after the plebiscite issue of 11th and 12th march 1860 San Casciano and the whole Toscana Region began being part of the Reign of Italy.