The ban of the Empire ought to be at least equally awful with that of the Church; disloyalty to the Emperor was as heinous a sin as infidelity to the head of Christendom; the independence of the Lombard republics was as a great and punishable political heresy. Even in Rome itself, as head of the Roman Empire, Frederick aspired to a supremacy which was not less unlimited because vague and undefined, and irreconcilable with that of the Supreme Pontiff. If ever Emperor might be tempted by the vision of a vast hereditary monarchy to be perpetuated in his house, the princely house of Hohenstaufen, it was Frederick. He had heirs of his greatness; his eldest son was King of the Romans; from his loins might yet spring an inexhaustible race of princes; the failure of his imperial line was his last fear. The character of the man seemed formed to achieve and to maintain this vast design; he was at once terrible and popular, courteous, generous, placable to his foes; yet there was a depth of cruelty in the heart of Frederick towards revolted subjects, which made him look on the atrocities of his allies, Eccelin di Romano, and the Salinguerras, but as legitimate means to quell insolent and stubborn rebellion.⁠ ⁠…