Meanwhile he had visited his native place, Vicenza, on invitation of the bishop, and had so impressed the people that they gave him their statutes to revise at his pleasure, and proclaimed him duke, marquis, and count of the city--titles which belonged to the bishop, who also offered to make over the episcopate to him. As at Verona, he used his power to burn a number of heretics. During his absence at Verona, Uguccione Pileo, an enemy of the Schia family, induced the people to revolt, when Giovanni hastened back and suppressed the rebellion, putting to death, with torture, a number of citizens, who are charitably supposed to have been heretics. Uguccione brought up reinforcements; a fierce battle was fought in the streets, and Giovanni was worsted and taken prisoner. A letter of condolence, addressed to him in prison, by Gregory, under date of September 22, 1233, serves to fix the date of this, and to show how powerless was the papacy to protect its agents in the fierce dissensions of the period. Giovanni was obliged to ransom himself and return to Verona, and thence to Bologna. The peace which he had effected was of short duration. The chronic wars broke out afresh, and Giovanni, at the instance of Gregory, came again to pacify them. In this he succeeded, but no sooner was his back turned than hostilities were renewed. Gregory made a third attempt, through the Bishops of Reggio and Treviso, who induced the warring factions to lay down their arms for a while; but the main object, of presenting a united front and keeping Frederic out of Italy, was lost, Ezzelin and a number of the cities urged his coming, and the decisive victory of Cortenuova, in November, 1237, dissolved the Lombard League which had so long held the empire in check, and made him master of Lombardy.[227] During all this time Gregory had been untiring in his efforts to subdue heresy in Lombardy, undeterred by the disheartening lack of result. All his legates to that province were duly instructed to regard this as one of their chief duties. In May, 1236, he had even attempted to establish there a rudimentary Inquisition, but, in the existing condition of the land, even he could hardly have expected to accomplish anything. Frederic came with professions that the extirpation of heresy was one of the motives impelling him to the enterprise; and when Gregory reproached him with suppressing the preaching of the friars and thus favoring heresy, he astutely retorted, with a reference to Giovanni, by alluding to those who, under pretext of making war on heresy, were busy in establishing themselves as potentates, and were taking castles as security from those suspect in faith. Gregory, in reply, could only disclaim all responsibility for the acts of the adventurous friar. Yet Gregory himself, when it suited his Lombard policy, did not hesitate to relax his severity against the heretics, and it became a popular cry in Germany that he had been bribed with their gold.[228]