Final answer:
The first part of Dante Alighieri's Divine Comedy, leading up to 'Purgatorio' and 'Paradiso', is called 'Inferno'. It is an allegorical journey through Hell, depicting the author's voyage through various levels of sin and virtue.
Step-by-step explanation:
The first part of the tripartite structure that includes Purgatorio and Paradiso is called Inferno. This literary work is part of Dante Alighieri's Divine Comedy, which is one of the most significant writings in the canon of Western literature. Inferno depicts the author's journey through Hell, guided by the Roman poet Virgil. The narrative is a complex representation of the afterlife, capturing the moral and theological principles of the time. It aligns with the historical depiction of the underworld, which is divided into various sections for sinners and virtuous souls, as seen in both Greek mythology and various philosophical traditions.
In Roman Catholic doctrine, Purgatorio is a space of suffering and purification after death, eventually leading one to heaven, as detailed through Dante's narrative. Paradiso represents the celestial realm of Heaven, completing Dante’s exploration of the afterlife. The entirety of Dante's work presents a profound allegorical map of the soul’s journey towards God.