Monteriggioni is a medieval walled town, located on a natural hillock, in the Siena Province of Tuscany - built by the Sienese in 1213 as a front line in their wars against Florence, by assuming command of the Cassia Road running through the Val d'Elsa and Val Staggia to the west.

Monteriggioni, which sits in the center of the Comune of Monteriggioni (an approximate 19.49 km² area around the town), is located fifteen kilometers from the Province's capital.

During the conflicts between Siena and Florence in the Middle Ages (in which Florence was seeking to expand territory), the city was strategically placed as a defensive fortification.
It also withstood many attacks from both the Fiorentini and forces controlled by the Bishop of Volterra. Eventually the Sienese were able to place control of the town's garrison to Giovannino Zeti, who had been exiled from Florence. In 1554, in an act of reconciliation with the Medicis, Zeti simply handed the keys of the town over to the Medicean forces - considered a "great betrayal" by the town's people.