in August, 1230, by which Frederick surrendered his claim over the Sicilian clergy and obtained in return the removal of the excommunication, which carried with it a tacit recognition of his crusade. [Sidenote: The Pope and Roman claims.] It was nine years before the struggle was openly renewed. There were many causes of difference in the interval, but Pope and Emperor found two occasions for common action. In the first place Gregory imitated the policy of his great relative in using every method for extending the immediate suzerainty of the Pope over the towns and barons within the Roman duchy. But despite Innocent's civic victory the Roman Commune desired to place themselves on a level with the other free cities of Italy such as Milan and Florence, and claimed jurisdiction over the whole district. Twice already had the Romans expelled Gregory and recalled him before they demanded from him, in 1234, the surrender of sovereign rights within the duchy. Gregory fled and appealed for help to Christendom; and Frederick supplied the troops which restored the Pope for the third time and forced the Romans to withdraw their claims. [Sidenote: Frederick and heresy.] Pope and Emperor also pursued a common policy against heretics. The Lateran Council of 1215 issued a series of ordinances against heretics, making it the duty of the secular power to punish them under pain of excommunication. But each country and even each city issued its own regulations for giving effect to the injunctions of the Council. Only gradually in the second quarter of the century was the old episcopal jurisdiction over heresy superseded by the establishment of the papal Inquisition. Meanwhile, in 1220 at his imperial coronation Frederick put out in his own name an edict for the secular suppression of heresy, which had been dictated to him from Rome. In 1231 this edict was enforced in Rome itself when Gregory IX established the Inquisition there and made it the business of the Senator, the head of the civic commune, to execute the sentences of the Inquisitor. The regulations now drawn up for the conduct of the secular power in such cases, were sent over all Europe with orders for their enforcement. In the same year Frederick renewed his attack upon heretics in his Sicilian Constitutions, and in the course of the next eight years he issued "a complete and pitiless code" of "fiendish legislation," placing the whole of the machinery of state at the disposal of the Inquisitor. But Gregory was not deceived. Rather he complained that Frederick's orthodoxy took the form of the punishment of his personal enemies, of whom many were good Catholics. Certainly Frederick's anti-heretical edicts were not prompted by religious zeal. He was more detached than any ruler of the Middle Ages from the current ideas of the time. He seems to have been, if it is possible, utterly non-religious. [Sidenote: Legislation of Emperor and Pope.]