As he begins the ascent Dante reminds himself that because Virgil is a spirit he has no shadow. The poet responds with a lecture about the nature of souls after death and the limits of human reason. Dante already finds his thinking clearer. Virgil reminds him that the human mind can never understand the infinite - and that this was the problem for many great minds in times past:-
For if ye had been able to see all,
no need was there for Mary to give birth;
And you have seen desiring without fruit,
those whose desire would have been quieted,
which evermore is given them for a grief...
The poets notice a band of souls, the excommunicates and amongst them a musician Manfred. He explains his presence: Pope Clement IV excommunicated him for "caring for neither God nor His saints". Accused of murders, he is here since at his death, he gave himself "weeping to Him, who willingly doth pardon." For this last minute action he and his band of excommunicates are destined to wander at the foot of Mount Purgatory for thirty times the length of their lives.-