The powerful fortress is at an altitude of 550 metres above sea level, on a hillside dominating the Era and the Cecina valleys. The building rests on a large rock of alberese stone which makes the northern slope impregnable.
The name ‘pietra cassa’ (broken stone) is derived from the cleft in the rock. The fortress is mentioned in a 1028 document dealing with an exchange of lands and castles. In 1115 the fortress was acquired, along with other castles in the Valdera, by the Bishop of Volterra. In 1202 the Pisans conquered many castles in the Valdera, including Pietracassia until 1286, when it was returned to Volterra. In 1405 the traitor Pietro Gaetani handed over Pietracassia and other castles in the Valdera to Florence. At the time the castle enclosed a small church. In 1434 Florence tore down the castles of Pietracassia, Orciatico and Lajatico in retaliation for their rebellion.
The fortress has a chiefly military character and is protected by a perimeter wall reinforced by angular towers. The wall runs all along the southern side of the complex, the northern side being protected by a cliff that constitutes an insurmountable natural barrier.
The inner and older nucleus has a quadrilateral plan with two imposing square towers. The fortress has only one access through the high wall. Inside, the tower surrounded by the former troop quarters and residences.
The fortress represents one of the most remarkable examples of castles in the early Middle Ages. The building dates back to the 8th century, which makes it one of the earliest castles of barbarian foundation in Tuscany
How to reach: suitably signposted on the road that from Lajatico leads to Orciatico and on the paths used by wild boar hunters, along road SP 14 to Miemo.
Note: Only a few hundred metres of the road are surfaced. After about 3 km of country road (in good condition) leave the car and continue on foot for about 2 km.