The great poem thus misnomered is partly a system of theology, partly an
abstract of the knowledge of the day, but chiefly a series of passionate
and imaginative pictures, altogether forming an account of the author's
times, his friends, his enemies, and himself, written to vent the spleen
of his exile, and the rest of his feelings, good and bad, and to reform
church and state by a spirit of resentment and obloquy, which highly
needed reform itself. It has also a design strictly self-referential.
The author feigns, that the beatified spirit of his mistress has
obtained leave to warn and purify his soul by shewing him the state of
things in the next world. She deputes the soul of his master Virgil
to conduct him through hell and purgatory, and then takes him herself
through the spheres of heaven, where Saint Peter catechises and confirms
him, and where he is finally honoured with sights of the Virgin Mary, of
Christ, and even a glimpse of the Supreme Being!

His hell, considered as a place, is, to speak geologically, a most
fantastical formation. It descends from beneath Jerusalem to the centre
of the earth, and is a funnel graduated in circles, each circle being a
separate place of torment for a different vice or its co-ordinates, and
the point of the funnel terminating with Satan stuck into ice. Purgatory
is a corresponding mountain on the other side of the globe, commencing
with the antipodes of Jerusalem, and divided into exterior circles of
expiation, which end in a table-land forming the terrestrial paradise.
From this the hero and his mistress ascend by a flight, exquisitely
conceived, to the stars; where the sun and the planets of the Ptolemaic
system (for the true one was unknown in Dante's time) form a series of
heavens for different virtues, the whole terminating in the empyrean, or
region of pure light, and the presence of the Beatific Vision.