The first part of Dante Alighieri's epic poem Divine Comedy, also known as Inferno, tells about the spiritual pilgrimage of Dante from Hell to Purgatory (Fiero 148). The Roman poet Virgil, who guides Dante through hell, acts as the symbol of reason and studies the varieties of human sin (Sayre 441). As a matter of fact, the Inferno serves as criticism of his Italian contemporaries, some from history and legend from his era, marred by the severity of their sin (Sayre 441). Alighieri opted to write Inferno as vernacular literature in order to address and apply its message of conflicting moralities to a wider audience, of and from medieval Italy, and to the world today.
In Canto IV, the poets Dante and Virgil begin to cross the first circle, Limbo. Here they find the virtuous pagans who were not saved, yet have not sinned (Raffa). The poets encounter the four great poets of Dante's time-Homer, Horace, Ovid, and Lucan-and welcomed Dante as part of the group (Alighieri III. 88-102). And to Dante's surprise, he found Aristotle among the souls in the "Citadel of Human Reason," who is described, "the master of those who know, ringed by the great souls of philosophy (Alighieri III. 131-132)." The philosophy of Aristotle influenced Albert the Great and Thomas Aquinas, two of Dante's favorite Christian thinkers, whom, Raffa notes, "strove to validate the role of reason and to sharpen its relationship to faith." Dante also had the influence of Aristotelian thought on him, notably in the content of the moral structure of hell, which explains his reaction upon the sight of Aristotle (Raffa). From this point on in Dante's journey, the role of reason becomes the precedent for the punishments in the upcoming circles. Aristotle, for example, defines human reason as the highest state man can achieve without God and observes that it distinguishes man from other life forms, but Dante provides a modified explanation that a man of reason cannot achieve a greater state without God's glory; by placing man before God, Aristotle can achieve no greater with human reason alone but the pain of no hope in the afterlife (Aristotle 17).