The Divine Comedy by Dante Alighieri
Dante’s classic fourteenth century poem is really three books in one, each describing the abode of those who have departed from this world. Inferno, describing the horrors of hell, was the most interesting to me, and has probably shaped the world’s view of hell more than the Bible has. Purgatoiro depicts purgatory, that once again has influenced Roman Catholic thought on this subject as much as anything. The final poem is Paradiso and is a picture of heaven, which I found relatively uninteresting.
The Divine Comedy has been reviewed thousands of times and needs no further thoughts from me. I will say that I was surprised by the blend of Medieval Christianity, pagan thought and mythology. Along with John Milton’s Paradise Lost, this work has molded the way many Christians view the next life, even though the vast majority of the contents are imaginary.