Here is the story, in brief. A lonely pilgrim—it is Dante himself—strays into a dark wood, and is guided by the Roman poet Virgil down into Hell to contemplate the harrowing fate of the damned.
He has taken it from one of the pastoral poems of Virgil.
Virgil alludes to just this passage in Homer when he describes the entrance of a whole crowd of people in to the underworld as "the falling of leaves in the early frost of autumn."
It's a poem deeply invested in the tradition of pastoral poetry, pastoral poetry from Theocritus and Virgil onward.
