Answer:
In the first circle of the Inferno, Dante sees non-Christians and pagans. There he sees Homer, Socrates, Aristotle, Cicero, Hippocrates, and Julius Caesar.
In the second circle of the Inferno, Dante sees people who were banished to the Inferno because of the lust and adultery. There he sees Cleopatra, Tristan, Helen of Troy.
In the third circle of the Inferno, Dante sees degraded people and gluttons, who were punished by lying in the vile produced by icy rain. There he sees Ciacco, a character who tells him that Guelphs (who supported Pope) will expel Ghibellines from Florence.
In the fourth circle, Dante sees greedy people and there he meets mostly cardinals, popes, and clergymen.
In the fifth circle, Dante sees people who committed serious sins during their life. There, he sees Filippo Argenti who confiscated Dante's property after he was expelled from Florence.
In the sixth circle, he sees heretics who are burning in flaming tombs. There he sees many historical figures, like Greek philosopher Epicurus, Holy Roman Emperor Frederick II, and Pope Anastasius II.
In the seventh circle, Dante sees murders, and violent people and he meets Alexander the Great, Dionysius I of Syracuse, and Guy de Montfort.
In the eighth circle, Dante sees fraudulent people, divided into 10 smaller circles (seducers, flatterers, prophets, hypocrites, corrupted people, etc.
In the last, ninth, circle, Dante sees people frozen in an icy lake. There he finds people who are condemned for treachery, divided into 4 rounds, named after historical characters like Cain, Antenor of Troy, Judas Iscariot, and Ptolemy.
