The town of Gambassi Terme occupies an area in the province of Florence that has been populated since the Neolithic. It is an ancient "land of passage" that rose along the most important Etruscan and Roman roads and near the Francigena way walked by pilgrims in the Middle Ages. It is set at 332 m. of altitude and it has a population of 4,500 inhabitants.

The fragments manufactured in red jasper that have been found in some areas of the town (such as Gambassi, Camporbiano, Boscotondo, Santa Cristina), testify the presence of Prehistoric men in the territory of Gambassi. Yet, an important and populated settlement appeared in the Archaic-Etruscan era around the VII century B.C. Human settlements in Gambassi lasted until the III century A.D. under the aegis of the Romans. The evidences unearthed during archaeological excavations, such as graves, Hellenic-Etruscan and late Roman finds, are numerous.
The document that allows tracing back the existence of the castle of Gambassi in the Middle Ages dates to 1037. It is a donation act with which Guido del fu Ranieri ceded part of his properties near the castle to the bishop of Volterra. With time, more donations caused the Castle of Gambassi to become a property of the bishops of Volterra until the end of the XII century. between 1172 and 1183 a "castrum novum", namely a small centre that almost immediately became a city-state, rose near the bishop's stronghold.
In the XIII century, "rectors" were autonomously elected. Despite this, it was a very troubled time for the inhabitants of Gambassi who were at the centre of the harsh fight between the population and the rural noblemen, first, and then it was at the centre of a dispute between the town of San Gimignano and the bishopric of Volterra. As regards the second conflict, the clashes between the bishopric and the town that occurred in 1230 and between 1278 and 1281 were particularly bloody. These wars ended with the incorporation of the castle of Gambassi within the Florentine jurisdiction in 1294.
Gambassi was raised to the status of Town Hall in 1322. The remains of a medieval glassworks have been found and they gave the chance to deepen the research on one of the pivots of the local economy, namely the activity of Gambassi's "bicchierai". The manufacture of glass was practised between the XII and the XVI centuries and it found a real fertile breeding ground both in Gambassi and in the nearby territories. In effect, woods that supply the material for furnaces, vegetal ashes and sand mines as well as quartziferous minerals, namely all what is needed in this kind of production, are present here.
Recently, more exactly since 1977, Gambassi has changed its name in order to enhance the spas of its territory. The baths of Gambassi were opened in 1974 and they supply aqua sorgiva ad alta mineralizazzione with scientifically therapeutic and healing properties.