[T]he deepest level of hell is reserved for traitors. Why traitors? Because they make life in community impossible. In medieval Italy, cities were in a frequent state of war with each other. When they closed the city gates at night, everybody in the city had to trust that no one would open the gates during the night and let in troops of the enemy. If you could not have that trust, you couldn't sleep. You couldn't live, for fear that your neighbor would betray you, and everyone, to the enemy. To render everyone isolated from everyone else, and living in fear - this was hell.