Built by the Genevans in 1161, over the remains of an already existing fortification, the castle of Portovenere dominates both the town and the eastern most point of the Gulf of Poets. The typical genevan military architecture is most evident in the two main buildings of the castle and in its powerful walls. The main entrance of the lower building gives onto the town, whilst the higher building, with its 16th century structure and the Ipostila room, houses the captain’s living quarters. The Ipostila room takes its name from the ancient temples, which were supported by fortified columns.
The evolution of offensive techniques and of firearms is present in the flat roof of the higher part of the building, which was probably added in the 16th century. The surrounding walls a reinforced by three ramparts facing out to sea, whereas the walls either side of the castle are joined together by a semicircular tower. Communication trenches run around the base of the walls, which are dotted with slit windows.
In the Neapolitan era, the Ipostila room was used to imprison political captives, and it is still possible to make out the marks left by the grilles today.