Between Hell proper, the place of punishment, and the vestibule, Dante places the circle of Limbo, devoted to those people who had no opportunity to choose either good or evil in terms of having faith in Christ. This circle is occupied by the virtuous pagans, those who lived before Christ was born, and by the unbaptized.
Many of the shades in Limbo are not really sinners, but people who were born before Christianity. These virtuous pagans live forever in a place of their creation. The shades that Dante singles out, such as Aristotle, Socrates, and Plato, lived by wisdom and thought, not religion, or at least not Dante's religion. Therefore, the Hell that they reside in allows them to reside in human wisdom, but without the light of God. Most of the first circle is in darkness, though Dante allows reason to create a small light of its own. Socrates, for example, wrote that he envisioned the afterlife as a place where one would have discussions with great people that came before or that lived in the present. Therefore, Socrates gained his ideal eternity.
Thus, Socrates is in Limbo, discussing philosophy and ethics with the other great souls that are there. In other words, Socrates attained the kind of afterlife that he, as a wise man, envisioned as the perfect one. His afterlife is not punishment; it is the failure of the imagination to envision the coming of Christ and faith in the coming of the Messiah. Moments after Virgil arrived in Limbo, he records that someone "in power crowned" appeared in Hell and took from there the shades of all the ancient patriarchs of the Old Testament, who had faith that the Messiah would some day come.
