Dante's Inferno is one of classics of Western literature. One of the things that makes it so engaging is that in each circle of hell a different category of sinner is suffering. For example, in Canto V, Dante encounters the second circle of hell. In this circle, sinners damned for their carnal sins suffer. This means they sinned due to lust. A number of specific lustful sinners are punished here: Semiramis, Cleopatra, Helen, Achilles, Paris, Tristan, and Francesca of Rimini. All of these are famous lovers from classic works of art, or in the case of Francesca of Rimini, contemporaries of Dante. This canto performs several functions. First, it shows that lust is far from the worst of the sins. Second, it displays Dante's knowledge of classic works of literature, and links his work of those. Third, it creates a connection between his contemporaries and classic figures, which elevates them even as it damns them.
This is a great question. The Inferno (hell) has many souls. Let me give you a list of them.
Circle One. Technically those here are not tortured. There are virtuous non-Christians, such as Homer, Socrates, Aristotle, and Julius Caesar.
Circle Two. The lustful. They are punished by being tossed by strong winds. For this reason, they find no peace. Helen of Troy and Cleopatra are here.
Circle Three. The Gluttons are punished by being forced to lie in a slush that is produced by icy rain.
Circle Four. The Greedy. Ironically there are many clergy members here.
Circle Five. The Angry. These people are angry and they are fighting each other.
Circle Six. The Heretics. Here heretics are in a burning tomb. Greek philosopher Epicurus, Holy Roman Emperor Frederick II, and Pope Anastasius II are here.
Circle Seven. The Violent Criminals. They are in boiling blood. Some here are: Dionysius I of Syracuse and Guy de Montfort.
Circle Eight. The Fraudulent. Those who committed falsehoods are here, such as politicians.
Circle Nine. The Traitors. These people are in an icy lake. Judas is infamous here.