Semproniano Castle (also known as the Aldobrandesca fortress) has been documented since 849. It stands on a hill between the Fiora and Albegna valleys and was built as a lookout point to defend the ancient village. Fortified by the Aldobrandeschi to guard the road that connects Arcidosso with Saturnia and Pitigliano, it was long disputed by Orvieto and Siena, until the latter conquered it in 1410. Today only a few ruins and sections of perimeter walls surrounded by cypresses and tall trees remain, however the quadrangular base of the ancient fortress and the adjacent tower are still clearly visible.
