Then they came to the Styx--the river of Hades, over which the
ferryman Cha'ron, grim and long-bearded, conveyed the departed
spirits, in his iron-colored boat, using a pole to steer with.

The watery passage Charon keeps
Sole warden of these murky deeps.
CONINGTON, _AEneid_, BOOK VI.

No living being was permitted to enter Charon's boat, or to cross the
Stygian river without the passport of the golden bough. This could be
obtained only by special favor of some powerful god, and few had been
so favored. Even the dead, if their bodies had not received burial
rites, were refused admission to the boat, until they had wandered on
the shore for a hundred years. So the Sibyl told AEneas when he
inquired why some were ferried over, while others were driven back,
lamenting that they were not allowed to pass to their destined abode.

"The ghosts rejected are the unhappy crew
Deprived of sepulchres and funeral due;
The boatman, Charon; those, the buried host,
He ferries over to the further coast;
Nor dares his transport vessel cross the waves
With such whose bones are not composed in graves.
A hundred years they wander on the shore;
At length, their penance done, are wafted o'er."
DRYDEN, _AEneid_, BOOK VI.

One of these unhappy spirits AEneas recognised as that of his pilot
Palinurus, who told the hero that he had not been drowned, or plunged
into the sea by a god, for he did not know of the treachery of Somnus.