Why did Gogol describe Dead Souls as a poem rather than simply a novel?

Nikolay Gogol subtitled his masterpiece Dead Souls a "poem" rather than a novel because he envisioned the work as a grand, multi-part prose equivalent to Dante’s Divine Comedy.1

Gogol intended the first volume to represent the Inferno of Russian life, exposing the corruption, serfdom, and moral decay of the era. He planned for the subsequent two parts to serve as a Purgatorio and Paradiso, detailing the moral regeneration of his protagonist, Chichikov. By labeling the work a "poem" or "epic," Gogol emphasized his ambition to move beyond mere social satire and instead reveal a righteous path for humanity to follow in an otherwise evil world.1