Frank Frost Abbott, Roman politics (1923)
“ Feudalism inculcated the idea that each man owed allegiance to some one above him, the vassal to his lord, the lord to the prince, the prince to the Emperor, and it was only natural to complete the system by deriving the power of the Emperor from the Pope, whose responsibility was to God. This conception of the Pope as the ultimate source of authority throughout the world with his seat in Rome continued the tradition of the unity of the Roman Empire, which, as we shall soon see, was one of the most potent influences at work throughout the Middle Ages. ”
