Not every one Dante commented about was in hell. In purgatory, Dante also saw Boniface, archbishop of Ravenna shortly before the story took place. Many of those seen in their respective destinations make a lot of sense based on their entries in Our Global Past . Those seen in heaven are generally considered saints or virtuous christians. Thomas Aquinas was a theologian who wrote about the laws that govern man.
Eternal law governs morality and nature.
Natural law governs what humans can know. Human laws are laws that governments and society impose on themselves. Finally, divine laws are laws that God puts on his people. An example would be the 10 commandments. Charlemagne was also seen in heaven.