Why did Frederick II fight the rebellious Sicilian barons?

Frederick II fought the rebellious Sicilian barons primarily to consolidate his rule and restore royal authority in the Kingdom of Sicily. During his minority, the kingdom had fallen into a state of anarchy, characterized by competing factions of nobility, foreign captains, and local interests that had seized control of royal properties and prerogatives.123

Upon returning to Sicily to reestablish his power, Frederick sought to revoke the various privileges that the nobility had usurped during his absence and the years of his minority. His efforts to regain these lost royal rights and centralize his administration—such as through the Assizes of Capua—met with significant resistance from a large segment of the nobility, necessitating military action to break their opposition and secure his control over the realm.13