Before the Dominicans were armed with the power of persecution Piero earnestly devoted himself to the original function of the Order, that of controverting heresy, and preaching against heretics. In this the success of the young apostle was marvellously aided by his thaumaturgic development. At Ravenna, Mantua, Venice, Milan, and other places, numerous wonders are related of his performance. Thus, at Cesena, the success of his efforts at conversion irritated the heretics, who, on one occasion, interrupted his preaching in the public square by volleys of filth and stones discharged from a house near by. He several times mildly entreated them to desist, but in vain, when, inspired by divine wrath, he launched a terrible imprecation against them. Instantly the house crumbled in ruin, burying the sacrilegious wretches, nor could it be rebuilt until long afterwards.[231] When the Dominicans were charged with the duty of persecution his earnest zeal naturally caused him to be selected as one of the earliest laborers. In 1233 he was sent to Milan, where, thus far, all the efforts of papal missives and legates had proved ineffectual to rouse the authorities and the citizens to undertake the holy work. The laws which, in 1228, Cardinal Goffredo had inscribed on the statute-book had remained a dead letter. All this was changed when Piero da Verona made his influence felt. Not only did he cause Gregory’s legislation of 1231 to be adopted in the municipal law, but he stimulated the podestà, Oldrado da Tresseno, and the archbishop, Enrico da Settala, to work in earnest. A number of heretics were burned, who were probably the first victims of fanaticism which Milan had seen since the time of the Cathari of Monforte. So strong was the impression made by these executions that they earned for the podestà Oldrado the honor of an equestrian portrait in bas-relief, with the inscription, “_Qui solium struxit, Catharos ut debuit uxit_,” which is still to be seen adorning the wall of the Sala del Consiglio, now the Archivio pubblico. It fared worse with the archbishop, who was rendered so unpopular that he was banished, for which the magistracy was duly excommunicated; but he, too, had posthumous reward, for his tomb bore the legend “_instituto inquisitore jugulavit hœreses_.” Piero likewise founded in Milan a company, or association, for the suppression of heresy, which was taken under immediate papal protection--the model of that which ten years later did such bloody work in Florence. We may safely assume that his fiery activity continued unabated, though we hear nothing of him until 1242, when we again find him in Milan so vigorously at work that he is said to have caused a sedition which nearly ruined the city.[232]