Perched on a hill three hundred feet high, between the sea and the Apennines hinterland, Guardistallo was a large village of Lombard origin with a castle and a keep still existing in 1833, under the rule of the ancient feud Gherardesca in 1154 that made it gift to the Bishop of Volterra.Posto under the domination of Pisa, it rebelled at the threat posed to the Republic of Pisa by Luchino Visconti. Reduced to obedience, followed the fortunes until victory, in 1406, of Florence, to whom he swore fidelity. Occupied by the army in 1447 by Alfonso of Aragon, King of Naples, was recaptured shortly afterwards by the Florentines against whom participated in the ill-fated rebellion led by Pisa.
Still offers many important finds of its medieval history, such as the ruins of the fortress, which is accessed through a door that retains many of its original character. Inside the fortress walls of the track are visible and some old houses. The town retains a medieval delicious corners included, at least in part, in their primary plan.