Ghosts appeared in Homer's Odyssey and Iliad, in which they were described as vanishing "as a vapor, gibbering and whining into the earth". Homer’s ghosts had little interaction with the world of the living. Periodically they were called upon to provide advice or prophecy, but they do not appear to be particularly feared. Ghosts in the classical world often appeared in the form of vapor or smoke, but at other times they were described as being substantial, appearing as they had been at the time of death, complete with the wounds that killed them.^[40]

By the 5th century BC, classical Greek ghosts had become haunting, frightening creatures who could work to either good or evil purposes. The spirit of the dead was believed to hover near the resting place of the corpse, and cemeteries were places the living avoided. The dead were to be ritually mourned through public ceremony, sacrifice and libations, or they might return to haunt their families. The ancient Greeks held annual feasts to honor and placate the spirits of the dead, to which the family ghosts were invited, and after which they were “firmly invited to leave until the same time next year”.^[41]

The 5th century BC play Oresteia contains one of the first ghosts to appear in a work of fiction.