The fortress was built about the year 1000 on the crag known as Sasso del Lupo, Wolf Rock. Its historic name, “Petra anellaria” derives from the circular shape of the rock on which it stands. It was restored and fortified by Francesco di Giorgio Martini in 1474. From 1506 to 1660 it was a fief of the illustrious Campofregoso family of Genoa; they transformed it into an aristocratic residence suitable for their elegant court.