Voion or Voeon was one of the cities of ancient Doric Tetrapolis of Phocis, according to Thucydides. Today at the foot of , ruins of the Acropolis are saved and other ancient buildings. Under the ruins of the citadel of Voion is now the village of of . It has been demonstrated by the findings that the area inhabited since the Mycenaean period to the present day uninterrupted.
The ancient Greek historians, like Herodotus and Thucydides, but also Pausanias subsequently referred to Voion, which was one of the main cities – states of central Greece. Pausanias specially mentions Voion with the name Xrusida, which dominates for the settlement to its recent history and note that it was 20 stadia from, the neighboring town which was destroyed during the Persian Wars, in 480 BC.
The ancient Voion is not sufficiently excavated; however the remains of the walls and towers of the city have been characterized as monuments since 1982. The citadel of Voion located on the hilltop of Agios Athanasios, so that has a panoramic view of the valley and the region linking it with Gravia, Lilaia, Mariolata and. Under the ancient citadel, has excavated an early Christian church, built at a basilica rhythm, which certifies the continuous occupation of the settlement in the history.
Voion today is easily visited from the village of Mariolata.