The Kingdom of Bohemia was a significant regional power during the Middle Ages. In 1212, King Ottokar I (bearing the title "king" since 1198) extracted a Golden Bull of Sicily (a formal edict) from the emperor Frederick II, confirming the royal title for Ottokar and his descendants and the Duchy of Bohemia was raised to a kingdom. Bohemian kings would be exempt from all future obligations to the Holy Roman Empire except for participation in the imperial councils. Charles IV set Prague to be the seat of the Holy Roman Emperor.