Italian literature began in his court, and many Saracenic customs of statecraft were transmitted through him from Palermo to Lombardy.
While Frederick foreshadowed the comparatively modern tyrants of the coming age, his Vicar in the North of Italy, Ezzelino da Romano, represented the atrocities towards which they always tended to degenerate.

Regarding himself with a sort of awful veneration as the divinely appointed scourge of humanity, this monster in his lifetime was execrated as an aberration from 'the kindly race of men,' and after his death he became the hero of a fiendish mythus.

But in the succeeding centuries of Italian history his kind was only too common; the immorality with which he worked out his selfish aims was systematically adopted by princes like the Visconti, and reduced to rule by theorists like Machiavelli.

Ezzelino, a small, pale, wiry man, with terror in his face and enthusiasm for evil in his heart, lived a foe to luxury, cold to the pathos of children, dead to the enchantment of women.

His one passion was the greed of power, heightened by the lust for blood.
Originally a noble of the Veronese Marches, he founded his illegal authority upon the captaincy of the Imperial party delegated to him by Frederick.