The medieval age is a period that marks the transition between the classical antiquity and the modern period. This era is divided into the High Middle Ages, where feudalism was established, and Late Middle Ages, in which the communes were born, city-states completely independent from feudal power. During the commune era there were continuous battles not just between the cities of Northern and Central Italy, but also within the cities, like the city of Florence where there were constant clashes between the political parties of the guelphs and the ghibellines. One of the greatest representatives of Italian culture and language at the time was Dante Alighieri, a florentin guelph that was banished from Florence because of Pope Boniface VIII. Dante wrote many important works, such as De Vulgari Eloquentia (The Eloquent Vernacular), Convivio (The Banquet), Vita Nova (The New Life) and the Divine Comedy. The Divine Comedy is a didactic-allegoric poem that is divided into three canticas: Hell, Purgatory and Paradise. The principles of the Divine Comedy are not solely ethical, they refer to the criminal law as well. The damned are punished in hell in accordance with the law of contrappasso, they suffer a punishment opposite of the sin committed in life or, in other cases, they suffer a punishment similar to the committed sin. In hell the souls are situated in the various circles in accordance to the severity of the sins. In the upper circles the sins are lighter, and they increase by going deeper into the pit, to the last circle. According to Dante, people commit crimes because of free will: they have the possibility to choose between good and evil. People are responsible for their own actions, so it is not human "nature" that determines them, but rather their bad behaviour. Criminal offences are transgressions of a criminal law and the deeds which become crimes are the ones that threaten society. Punishments are harms inflicted to the responsible persons of the crimes. That harm can be either suffering a physical pain or the deprivation of a pleasure or a good. In hell, Minos is the infernal judge who examines the committed sins and sends the souls to their place of atonement. The sinners confess all of their sins in front of Minos and the judge takes into consideration the most characteristic sin of that cursed soul. The same method was used in the real society of Middle Ages, even if it was harder to apply it, since the offender didn't want to confess. In that case alternative methods of persuasion were used, including torture. The results of this research have proven that Dante actually took a cue from the criminal law of the Middle Ages while writing his work. It has also shown that the punishments of all the sinners are not just a mere product of the poet's fantasy, but rather they coincide with the literary transposition of the penitential books that were current in his era.