In 1228, he had a falling-out with Duke Louis of Bavaria, who was suspected of plotting with Pope Gregory IX against Emperor Frederick II. Around Christmas of that year, Henry took over the rule for himself, forced Louis to submit, and then turned against the Bishop of Straßburg. 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. The emperor was dependent on the support of the princes for his Italian policies against the Pope. Among other things which augmented the discord between father and son, Frederick lifted several regulations Henry had stipulated during his minority years to reduce his authority, and on the other side, the elevation of the Swabian count Egeno V of Urach, a staunch enemy of the Emperor, who became the most important of Henry's advisers.