Ad Abolendam (1184) and 4th Lateran Council (1215)
We excommunicate and anathematize every heresy raising itself up against this holy, orthodox and catholic faith which we have expounded above. We condemn all heretics, whatever names they may go under. They have different faces indeed but their tails are tied together inasmuch as they are alike in their pride. Let those condemned be handed over to the secular authorities present, or to their bailiffs, for due punishment. Clerics are first to be degraded from their orders. The goods of the condemned are to be confiscated, if they are lay persons, and if clerics they are to be applied to the churches from which they received their stipends. Those who are only found suspect of heresy are to be struck with the sword of anathema, unless they prove their innocence by an appropriate purgation, having regard to the reasons for suspicion and the character of the person. Let such persons be avoided by all until they have made adequate satisfaction. If they persist in the excommunication for a year, they are to be condemned as heretics. Let secular authorities, whatever offices they may be discharging, be advised and urged and if necessary be compelled by ecclesiastical censure, if they wish to be reputed and held to be faithful, to take publicly an oath for the defence of the faith to the effect that they will seek, in so far as they can, to expel from the lands subject to their jurisdiction all heretics designated by the church in good faith. Thus whenever anyone is promoted to spiritual or temporal authority, he shall be obliged to confirm this article with an oath. If however a temporal lord, required and instructed by the church, neglects to cleanse his territory of this heretical filth, he shall be bound with the bond of excommunication by the metropolitan and other bishops of the province. If he refuses to give satisfaction within a year, this shall be reported to the supreme pontiff so that he may then declare his vassals absolved from their fealty to him and make the land available for occupation by Catholics so that these may, after they have expelled the heretics, possess it unopposed and preserve it in the purity of the faith — saving the right of the suzerain provided that he makes no difficulty in the matter and puts no impediment in the way. The same law is to be observed no less as regards those who do not have a suzerain.
Catholics who take the cross and gird themselves up for the expulsion of heretics shall enjoy the same indulgence, and be strengthened by the same holy privilege, as is granted to those who go to the aid of the holy Land. Moreover, we determine to subject to excommunication believers who receive, defend or support heretics. We strictly ordain that if any such person, after he has been designated as excommunicated, refuses to render satisfaction within a year, then by the law itself he shall be branded as infamous and not be admitted to public offices or councils or to elect others to the same or to give testimony. He shall be intestable, that is he shall not have the freedom to make a will nor shall succeed to an inheritance. Moreover nobody shall be compelled to answer to him on any business whatever, but he may be compelled to answer to them. If he is a judge sentences pronounced by him shall have no force and cases may not be brought before him; if an advocate, he may not be allowed to defend anyone; if a notary, documents drawn up by him shall be worthless and condemned along with their condemned author; and in similar matters we order the same to be observed. If however he is a cleric, let him be deposed from every office and benefice, so that the greater the fault the greater be the punishment. If any refuse to avoid such persons after they have been pointed out by the church, let them be punished with the sentence of excommunication until they make suitable satisfaction. Clerics should not, of course, give the sacraments of the church to such pestilent people nor give them a christian burial nor accept alms or offerings from them; if they do, let them be deprived of their office and not restored to it without a special indult of the apostolic see. Similarly with regulars, let them be punished with losing their privileges in the diocese in which they presume to commit such excesses.
“There are some who holding to the form of religion but denying its power (as the Apostle says) , claim for themselves the authority to preach, whereas the same Apostle says, How shall they preach unless they are sent? Let therefore all those who have been forbidden or not sent to preach, and yet dare publicly or privately to usurp the office of preaching without having received the authority of the apostolic see or the catholic bishop of the place”, be bound with the bond of excommunication and, unless they repent very quickly, be punished by another suitable penalty. We add further that each archbishop or bishop, either in person or through his archdeacon or through suitable honest persons, should visit twice or at least once in the year any parish of his in which heretics are said to live. There he should compel three or more men of good repute, or even if it seems expedient the whole neighbourhood, to swear that if anyone knows of heretics there or of any persons who hold secret conventicles or who differ in their life and habits from the normal way of living of the faithful, then he will take care to point them out to the bishop. The bishop himself should summon the accused to his presence, and they should be punished canonically if they are unable to clear themselves of the charge or if after compurgation they relapse into their former errors of faith. If however any of them with damnable obstinacy refuse to honour an oath and so will not take it, let them by this very fact be regarded as heretics. We therefore will and command and, in virtue of obedience, strictly command that bishops see carefully to the effective execution of these things throughout their dioceses, if they wish to avoid canonical penalties. If any bishop is negligent or remiss in cleansing his diocese of the ferment of heresy, then when this shows itself by unmistakeable signs he shall be deposed from his office as bishop and there shall be put in his place a suitable person who both wishes and is able to overthrow the evil of heresy.