The term Necromanteion translates to "Oracle of the Dead." It sits in the village of Mesopotamos, where the Acheron ("Joyless") River merges with Kokytos ("Lament") and Pyriflegethontas ("Burning Coals"), on the northwestern banks of Lake Acherousia, which is the door to the realm of the dead.
Perched atop a hill, the Necromanteion was frequented by those from Akrotiri Heimerio in Ammoudia, seeking to commune with the spirits of their departed. Herodotus recounts how Periander, the 6th-century BC tyrant of Corinth, sent emissaries to the Oracle to question his late wife, Melissa. In Homer’s Odyssey, the Necromanteion is also described as the passage through which Odysseus descended to the underworld.
The Necromanteion had operated continuously for about two centuries, until it was looted and burnt during the Roman conquest of Macedonia in 167 BC. In the first century, its courtyard was once again occupied - when Roman settlers arrived in Acheron. In the 18th century, a monastery dedicated to St. John the Baptist was built at the site. The identification of the ruins as the Necromanteion has been questioned, with scholars suggesting they may instead be remains of a military fortification or an agricultural tower. But, for now, it is identified as the Necromanteion and treated as such.