recently dead were, as a rule, called up, for it was naturally held that
they would feel greater interest in the world they had just left, and in
the friends and relations still alive, to whom they were really
attached. Not that it was impossible to evoke the ghosts of those long
dead, if it was desired. Even Orpheus and Cecrops were not beyond reach
of call, and Apollonius of Tyana claimed to have raised the shade of
Achilles.[56]

All oracles were originally sacred to Persephone and Pluto, and relied
largely on necromancy, a snake being the emblem of prophetic power.
Hence, when Apollo, the god of light, claimed possession of the oracles
as the conqueror of darkness, the snake was twined round his tripod as
an emblem, and his priestess was called Pythia. When Alexander set up
his famous oracle, as described by Lucian, the first step taken in
establishing its reputation was the finding of a live snake in an egg in
a lake. The find had, of course, been previously arranged by Alexander
and his confederates.

We still possess accounts of the working of these oracles of the dead,
especially of the one connected with the Lake of Avernus, near Naples.
Cicero[57] describes how, from this lake, "shades, the spirits of the
dead, are summoned in the dense gloom of the mouth of Acheron with salt
blood"; and Strabo quotes the early Greek historian Ephorus as relating
how, even in his day, "the priests that raise the dead from Avernus live
in underground dwellings, communicating with each other by subterranean
passages, through which they led those who wished to consult the oracle
hidden in the bowels of the earth." "Not far from the lake of Avernus,"
says Maximus of Tyre, "was an oracular cave, which took its name from
the calling up of the dead. Those who came to consult the oracle, after
repeating the sacred formula and offering libations and slaying victims,