What are examples of allegory in Dante's Inferno?

Dante's "Divina Commedia" is full of allegories; medieval authors made large use of them. However, why chose an Italian poet? I will answer, but I am afraid the very power of the poetic image will be lost in (my) translation.

In the first canto, Dante arrives to a wild forest that covers the mouth of the Inferno he is preparing to enter. There, he encounters three wild beasts that would attack him if it were not for the intervention of Virgil who comes to his rescue. The three beasts are obviously allegorical of the long path of redemption he is undertaking. The first one is a feline, possibly a leopard, representing lust and yearning; the second is a wolverine, representing greed and finally the third is a lion, representing the pride that he has to overcome (but fortunately never managed to) to be admitted to the higher echelons of the purification ladder.

In the 5th canto Dante encounters two lovers, Paolo and Francesca, murdered by the jealous husband. He places them in Hell. He cannot do otherwise because of their sin. But his heart is with them and, indirectly, he places the husband at an even lower circle of damnation. He calls them to hear their story and "they fly to him like two loving pigeons summoned by their common wish" (come colombe dal desio chiamate). I hope this helps.