As above the Divine Comedy is a poem where Dante is lead through the three realms of the dead.Virgil leads him through the first two, Hell and Purgatory. Beatrice, a woman Dante met in childhood and loved, leads him through heaven.
Dante meets loads of people including, Horace, Homer, Ovid and Lucan the poets and Socrates and Plato the philosophers.
Ceberus (the dog)is present in the third circle of Hell.
They go to heaven and meet lots of Saints, Constantine and others. I'm sure theres lots of boss and demon associations but theres so much...
Wiki has Mass info on it. GREAT book...