The German princes, angered by his city-friendly policies, forced him however to issue in Worms on 1 May 1231 the Statutum in favorem principum, directed against the cities, and by their complaints turned Frederick II against his son.
Pangeran-pangeran Jerman tidak senang akan kebijakan-kebijakan kotanya, mendesaknya untuk menerbitkan di Worms pada tanggal 1 Mei 1231 Statutum in favorem principum, yang ditujukan melawan kota-kota, dan dengan keluhan mereka menjadikan Friedrich II melawan putranya.