The most famous nekromanteion (or nekyomanteion), or oracle of the dead, of the ancient Greek world lies near the northwest shores of the Acherousian Lake, where Acheron and Kokytos, the rivers of Hades, meet. Ancient literary sources describe the Acherousian Lake as the place where the dead began their descent to Hades, and associate Ephyra, the Epirote city located further north, with the ancient cult of the god of death. The nekromanteion attracted people wishing to meet the souls of the dead, as these were able to foresee the future after having left their body. Homer provides the earliest reference to the nekromanteion of Acheron in his Odyssey, when Circe advises Ulysses to meet Teiresias, the blind seer, in the underworld in order to get an oracle for his return to Ithaka (k, 488, etc). Homer also gives a vivid account of the mortal Odysseus's descent to Hades (l, 24, et.c.). The resemblance between the setting described by Homer and the site of the nekromanteion is astonishing, a fact also noted almost one thousand years later by Pausanias, who argues that Homer had visited this area (1.17.5). Other Greek heroes also attempted the descent into Hades: Orpheus seeking to bring back his beloved Eurydice, Hercules in his search for Cerberus, the tree-headed dog guarding the exit from Hades, whom King Eristheas had asked for, and Theseus with Peirithos in order to seize Persephone.
Three Mycenaean children's graves (fourteenth-thirteenth centuries BC) with a small number of grave gifts are the earliest traces of activity on the hill, where the nekromanteion was established. Pottery sherds and fragments of terracotta figurines from the west foot of the hill dating up to the mid-seventh century BC indicate that a sanctuary dedicated to the Earth goddess was later founded in this area. The remains of the actual nekromanteion date from the Hellenistic period. These comprise the sanctuary's main building, erected in the early Hellenistic period (late fourth-early third century BC), and an annex of the late third century BC, which consisted of a central courtyard surrounded by rooms and warehouses. The sanctuary operated in this form continuously for approximately two centuries, but was burnt down and ceased to function after the Roman conquest of Macedonia in 167 BC. The sanctuary's courtyard was occupied once again in the first century, when Roman settlers arrived in the plain of Acheron. The convent of Agios Ioannis Prodromos and its cemetery were established over the ancient ruins in the early eighteenth century.
Excavated in 1958-1964 and 1976-1977 by the Archaeological Society at Athens, the nekromanteion of Acheron was the first sanctuary and oracle of the gods of the underworld to be brought to light.