They are contrasted types of the spirit of good and the spirit of evil conquering in man.

Up to a certain point in life their conduct is much alike.

Both belong to the Church--one as a priest, one as a layman affiliated to the Church.

The lust of money and self, when the character of Pompilia forces act, turns Guido into a beast of greed and hate.

The same character, when it forces act, lifts Caponsacchi into almost a saint.