their sins and prepared to enter heaven, Dante invokes the aid of the
muses. Then, gazing about him, he discovers he is in an atmosphere of
sapphire hue, all the more lovely because of the contrast with the
infernal gloom whence he has just emerged. It is just before dawn, and
he beholds with awe four bright stars,--the Southern Cross,--which
symbolize the four cardinal virtues (Prudence, Justice, Fortitude, and
Temperance).

After contemplating these stars awhile, Dante, turning to the north to
get his bearings, perceives Virgil has been joined in this
ante-purgatorial region by Cato, who wonderingly inquires how they
escaped "the eternal prison-house."

Virgil's gesture and example have meantime forced Dante to his knees,
so it is in this position that the Latin poet explains how a lady in
heaven bade him rescue Dante--before it was too late--by guiding him
through hell and showing him how sinners are cleansed in Purgatory.
The latter part of Virgil's task can, however, be accomplished only if
Cato will allow them to enter the realm which he guards. Moved by so
eloquent a plea, Cato directs Virgil to wash all traces of tears and
of infernal mirk from Dante's face, girdle him with a reed in token
of humility, and then ascend the Mount of Purgatory,--formed of the
earthy core ejected from Hades,--which he points out in the middle of
a lake with reedy shores.

Leading his charge in the early dawn across a meadow, Virgil draws his
hands first through the dewy grass and then over Dante's face, and,
having thus removed all visible traces of the passage through Hades,
takes him down to the shore to girdle him with a pliant reed, the
emblem of humility.