Heresy
Overview: What is heresy?
The word originally meant something like "sect." In the ancient world (it's a Greek word) it was applied not only to religious groups—usually dissenting or minority groups—but also to various schools of philosophers. Among the Christians, it meant groups who disagreed with whatever group the writer identified with.
This came to a head in the wake of the great persecutions of the 3rd century. In the face of those persecutions many Christians were martyred but many other Christians renounced their religion. Around the same time, significant differences developed over the nature of the Trinity and of Christ. Once Constantine made Christianity a tolerated religion, the Church faced difficult decisions about what to do about those differences and what to do about those who had fallen away from the faith. As those decisions were made, some inevitably were included while others were excluded. Those excluded were labelled heretics, but they were numerous enough to make the whole question of heresy a volatile one for many generations.
By the Middle Ages, then, a heretic was someone who claimed to be a Christian, but whose proclaimed beliefs or practices contradicted the core tenets of the Church (whether Orthodox or Roman Catholic). This is in contrast with an infidel, who was one who had heard the Christian message but rejected it, and a pagan, who was someone who had yet to hear the Christian message. There could also be an apostate, who is someone who had once been Christian but who converted to another religion (most commonly in the Middle Ages this was a pagan who had converted and then returned to the native religion).
Heresy was fairly clearly defined in the Church. Just because a person proclaimed a peculiar belief did not instantly make the person a heretic. The belief had to be held consitently and obstinantly; that is, the heretic had to be given a chance to recant his views. Only when shown the error of his ways and yet held to them could an individual rightly be declared to be a heretic.
It's also worth pointing out, because we see a lot of this in the late Middle Ages, that a person (usually a theologian) could develop an argument that in itself was not heretical but that could have logical corollaries that were judged heretical. In such cases, the propositions themselves could be condemned as heresy or as "erroneous" (a word that had a specific meaning in canon law), while the person himself was not accused of being a heretic.
Who decides what is heresy?
The Church, obviously, but "the Church" is an abstraction and abstractions don't decide anything. As a practical matter, the putative heretic would be accused by somebody. That somebody might be university professors, clergymen, or monks (often, in our period, Franciscans or Dominicans). The accusation would be taken either to the local bishop, or in some cases directly to the pope.
In either case, the matter would be reviewed by a panel of experts. There was room here for something like intellectual skullduggery. For example, a Dominican might condemn you and the experts who reviewed the accusation might also be Dominicans, more or less guaranteeing condemnation. I don't know of any specific instances of this, but would be glad of a reference.
The key thing to keep in mind here is that while the conclusion might be pretty predictable, condemnation for heresy was a formal process and was not the work of a single individual. The pope didn't go around declaring heretics on his own. You'll see the details when we turn to Wyclif and Hus.
What happens to a heretic?
Burned at the stake, right? Well, not always. Not even usually.
The Church could declare a person a heretic. If that person were a member of the clergy, the Church could take certain actions; the local bishop could, for example, take away the cleric's benefices or forbid him to preach or to publish. It could excommunicate the individual, removing him from the community of Christians and denying him the sacraments. As most heretics genuinely believed they were true Christians, these actions might be taken very seriously, though others might dismiss them. The Cathars, for example, had their own churches and rejected the Catholic ceremonies anyway.
If the heretic were a layman, the Church could also resort to excommunication, but not to much more than that. The Church had no authority to impose fines, to imprison, to seize property, stil less to execute, a layman. All these were matters for the secular authorities.
What the Church could and did do, was to recommend action. The local bishop, or the pope, could condemn the heretic (who might very well be incarcerated at the time) and then turn him or her over to the public authorities with a recommendation for execution.
It was the state, then, that burned people at the stake, not the Church. That might sound like a legal nicety, but it was more than that. Lords could and did choose to impose lesser penalties on the condemned—that happened very often in the case of the Cathars in 13th century France, for example. If a heretic were executed, it was because the public authorities were in agreement with the religious authorities that the person was dangerous—deadly dangerous. On the other hand, if the local secular authorities were in agreement with the orthodox position, then the whole power of the state as well as the church might be directed against the heretics. This happened to the Waldenses in the 15th century, who had enjoyed local protection for some generations, but were eventually hunted down and marginalized though not eliminated.
Why all the fuss?
We who live in modern political systems have a lot of trouble with the idea of condemning someone for heresy because we hold freedom of speech as a near-sacred ideal. But heresy is about much more than freedom of speech. It's more on the level of spilling military secrets in time of war. It's the social equivalent of a bizarre death cult that leads astray the young. It has the emotional impact of the most disgusting, reprehensible racist or sexist hate tract you can think of. Those are the sorts of things that tend to engender widespread agreement in modern society that a thing is bad and must be stopped. It's the sort of thing that leads law-biding citizens to ignore the law, to agree that the evil must be fought and legal procedures might be ignored. That's the sort of attitude most people had towards heresy.
A heretic was someone who was willfully spreading lies. You could argue over whether or not he was a heretic. As long as the heretical nature of the views was still debated, then a community or society could be divided. But if folks generally concluded that this was indeed a heresy, and the heretic obstinantly refused to desist, then execution or some similarly drastic action was in order. Few voices were ever raised in disagreement with this.
Every society has its limits, or else it's not a society. Heresy was not merely a matter of an oppressive religious hierarchy imposing its views on an unwilling or duped people. It was a matter of a community agreeing on certain inviolable principles (Americans like to talk about "inalienable rights"), and of agreeing to take drastic actions against those who would willingly violate those principles.
That said, there was plenty of room not only for abuse, but for honest and tragic error in all this. In the late Middle Ages, in particular, it was a matter of a Church hierarchy threatened by new forms of religious expression that were very close to heresy. Should they be allowed? Moderate forms seemed all right, but more radical forms were more threatening. Where to draw the line, and who should draw it? Some Church leaders drew the line here, others drew it there. Some were tolerant, others intolerant. It's very important to remember this as you read the religious history of the late Middle Ages. There was nothing even approaching unanimity regarding right doctrine and practice within Christendom.
That last question—who should draw the line of orthodoxy—turned out to be the most vexing, for heresy got tangled up with issues of national identity and local political control. The heresies of the late Middle Ages have a distinctly national flavor to them, and you cannot understand the movements themselves without knowing something about the political context. Rather than belabor the point, let's move on to look at specific instances: the Lollards, the Hussites, the Waldenses, and the Spiritual Franciscans.