Frederick held a diet in Mainz on 27 March 1188. Because of its purpose, he named the diet the "Court of Christ". The archbishop of Cologne submitted to Frederick and peace was restored to the empire. Bishop Godfrey of Würzburg preached a crusade sermon and Frederick, at the urging of the assembly, took the cross. He was followed by his son, Duke Frederick VI of Swabia, and by Duke Frederick of Bohemia, Duke Leopold V of Austria, Landgrave Louis III of Thuringia and a host of lesser nobles.