The unique feature of the Council of Constance is that it wasn't primarily focused on Hus. Had he not been later identified as a bridge between Wycliffe and Luther, his trial at the Council would have been a mere footnote.
Hus agitated not for what would be understood by today's theologians as Protestantism, but for a blending of Catholicism and Orthodoxy: he sought to establish a married priesthood, vernacular masses and reception of the Eucharist under the form of both bread and wine, Orthodox practice, while maintaining a more Roman-style openness of the mass.
The Council of Constance was founded to be an attempt at reconciliation between Catholic and Orthodox, and among the represented theologians, was a smashing intellectual success (although it failed politically once the Orthodox bishops went home). In fact, the Catholic Church consented to the demands of Orthodox practice, while the Orthodox recognized the validity of Catholic theology.
(The recision of the concessions to the Hussites/Orthodoxy occurred only after the collapse of the Catholic-Orthodoxy union.)
Thus, while Protestants love to paint Hus as a first martyr, the theological success of the Council of Constance makes it difficult to support the notion that the Catholics somehow had it in for Hussite theology, and concocted false legends of Hus's teachings: the Catholic and Orthodox bishops were trying to achieve the very stated goals of Hus.
The big sticking point, however, was that the Catholic and Orthodox were moving towards an agreement for a join defense of Constantinople in the face of a Muslim onslaught, recognizing that the ecclesial disunity posed an existential threat. Hus, on the other hand, was a declared pacifist, who condemned Crusades as manslaughter.
(While Hus' motives may well have been reform, Wycliffe, incidentally, was commission by the British crown, which sought a basis for refusing to join in the defense of Christendom from Islam. Far from the grass-roots free-thinker he is portrayed as, Wycliffe was actually a propagandist for hire.)
Also, please understand that Hus was not killed for heresy. And again, I offer this not as a defense for his killing, but for an understanding of the theology and ecclesiology involved. Allow me to explain:
During the Middle Ages, nominally Christian kings routinely killed their political opponents while making the excuse that they were punishing heretics. Appalled at this defamation of Christianity, the papacy established that it was up to the Church to determine who were heretics, as a means of protecting political dissidents. Hus was tried by the Catholic Church for heresy. Finding him guilty, the State's charges against him were allowed to proceed.
So why did the State execute him? The Church recorded their contradiction of his heresies as part of the Council of Constance (and yes, the leaders of the Orthodox churches present concurred.) But I do not find the State's case. My guess, however, is that article 30 was found to be treasonous:
30. Nobody is a civil lord, a prelate or a bishop while he is in mortal sin. {If accepted as doctrine, this would allow any slander or calumny to justify an insurrection.}
The other articles:
The condemned statements of Hus are as follows:
Condemned articles of J. Hus]
1. There is only one holy universal church, which is the total number of those predestined to salvation. It therefore follows that the universal holy church is only one, inasmuch as there is only one number of all those who are predestined to salvation. {Note that the Catholic Church does NOT condemn predestination.}
2. Paul was never a member of the devil, even though he did certain acts which are similar to the acts of the church's enemies.
3. Those foreknown as damned are not parts of the church, for no part of the church can finally fall away from it, since the predestinating love that binds the church together does not fail.
4. The two natures, the divinity and the humanity, are one Christ. {This is really subtle Christology. The Catholic Church insists that there are two natures of Christ, but that that which is human is not divine, and that which is divine is not human; from this refutation, perhaps Hus was asserting something similar to a Mormon Christology.}
5. A person foreknown to damnation is never part of the holy church, even if he is in a state of grace according to present justice; a person predestined to salvation always remains a member of the church, even though he may fall away for a time from adventitious grace, for he keeps the grace of predestination.
6. The church is an article of faith in the following sense: to regard it as the convocation of those predestined to salvation, whether or not it be in a state of grace according to present justice.
7. Peter neither was nor is the head of the holy catholic church.
8. Priests who live in vice in any way pollute the power of the priesthood, and like unfaithful sons are untrustworthy in their thinking about the church's seven sacraments, about the keys, offices, censures, customs, ceremonies and sacred things of the church, about the veneration of relics, and about indulgences and orders. {This would require that priests who were in vice would thus render moot the salvation of their flock; Rather the Catholic position is that the faith of the congregants in no way depends on the faithfulness of the priests who administer the sacraments to them.}
9. The papal dignity originated with the emperor, and the primacy and institution of the pope emanated from imperial power.
10. Nobody would reasonably assert of himself or of another, without revelation, that he was the head of a particular holy church; nor is the Roman pontiff the head of the Roman church.
11. It is not necessary to believe that any particular Roman pontiff is the head of any particular holy church, unless God has predestined him to salvation.
12. Nobody holds the place of Christ or of Peter unless he follows his way of life, since there is no other discipleship that is more appropriate nor is there another way to receive delegated power from God, since there is required for this office of vicar a similar way of life as well as the authority of the one instituting.
13. The pope is not the manifest and true successor of the prince of the apostles, Peter, if he lives in a way contrary to Peter's. If he seeks avarice, he is the vicar of Judas Iscariot. Likewise, cardinals are not the manifest and true successors of the college of Christ's other apostles unless they live after the manner of the apostles, keeping the commandments and counsels of our lord Jesus Christ.
14. Doctors who state that anybody subjected to ecclesiastical censure, if he refuses to be corrected, should be handed over to the judgment of the secular authority, are undoubtedly following in this the chief priests, the scribes and the pharisees who handed over to the secular authority Christ himself, since he was unwilling to obey them in all things, saying, It is not lawful for us to put any man to death; these gave him to the civil judge, so that such men are even greater murderers than Pilate.
15. Ecclesiastical obedience was invented by the church's priests, without the express authority of scripture.
16. The immediate division of human actions is between those that are virtuous and those that are wicked. Therefore, if a man is wicked and does something, he acts wickedly; if he is virtuous and does something, he acts virtuously. For just as wickedness, which is called crime or mortal sin, infects all the acts of a wicked man, so virtue gives life to all the acts of a virtuous man.
17. A priest of Christ who lives according to his law, knows scripture and has a desire to edify the people, ought to preach, notwithstanding a pretended excommunication. And further on: if the pope or any superior orders a priest so disposed not to preach, the subordinate ought not to obey.
18. Whoever enters the priesthood receives a binding duty to preach; and this mandate ought to be carried out, notwithstanding a pretended excommunication.
19. By the church's censures of excommunication, suspension and interdict the clergy subdue the laity, for the sake of their own exaltation, multiply avarice protect wickedness and prepare the way for antichrist. The clear sign of this is the fact that these censures come from antichrist. In the legal proceedings of the clergy they are called fulminations, which are the principal means whereby the clergy proceed against those who uncover antichrist's wickedness, which the clergy has for the most part usurped for itself.
20. If the pope is wicked, and especially if he is foreknown to damnation, then he is a devil like Judas the apostle, a thief and a son of perdition and is not the head of the holy church militant since he is not even a member of it.
21. The grace of predestination is the bond whereby the body of the church and each of its members is indissolubly joined with the head.
22. The pope or a prelate who is wicked and foreknown to damnation is a pastor only in an equivocal sense, and truly is a thief and a robber.
23. The pope ought not to be called "most holy" even by reason of his office, for otherwise even a king ought to be called "most holy" by reason of his office and executioners and heralds ought to be called "holy", indeed even the devil would be called "holy" since he is an official of God.
24. If a pope lives contrary to Christ, even if he has risen through a right and legitimate election according to the established human constitution, he would have risen by a way other than through Christ, even granted that he entered upon office by an election that had been made principally by God. For, Judas Iscariot was rightly and legitimately elected to be an apostle by Jesus Christ who is God, yet he climbed into the sheepfold by another way.
25. The condemnation of the forty-five articles of John Wyclif, decreed by the doctors, is irrational and unjust and badly done and the reason alleged by them is feigned, namely that none of them is catholic but each one is either heretical or erroneous or scandalous.
26. The viva voce agreement upon some person, made according to human custom by the electors or by the greater part of them, does not mean by itself that the person has been legitimately elected or that by this very fact he is the true and manifest successor or vicar of the apostle Peter or of another apostle in an ecclesiastical office. For, it is to the works of the one elected that we should look irrespective of whether the manner of the election was good or bad. For, the more plentifully a person acts meritoriously towards building up the church, the more copiously does he thereby have power from God for this.
27. There is not the least proof that there must be one head ruling the church in spiritual matters who always lives with the church militant. {"Church militant" is the Catholic term for living Christians, who must as a result of their fallen nature must combat the devil.}
28. Christ would govern his church better by his true disciples scattered throughout the world, without these monstrous heads.
29. The apostles and faithful priests of the Lord strenuously governed the church in matters necessary for salvation before the office of pope was introduced, and they would continue to do this until the day of judgment if--which is very possible--there is no pope.
Two things I want to comment on:
In post 8 you said that
He ran afoul of Church authorities on the doctrine of “impanation.” That is that the bread of the Mass remains bread, and the wine remains wine. Catholicism teaches that each the bread and wine are transubstantiated into the body, blood, soul and divinity.
However, I do not see that charge in the list you posted, and one of the sources I linked says he did not accept Wycliffe's view on the matter:
Jan Hus did not accept carte blanche all that Wycliffe taught. He did not, for example, accept Wycliffe's doctrine of remanence with respect to the Eucharist, or Mass. The doctrine of remanence held that in the celebration of the Eucharist, the bread and wine retain their material substance. Thus it denied the alleged miracle of transubstantiation by which, according to the Roman Catholic Church, the bread and wine became the flesh and blood of Christ. Transubstantiation was the key to the whole edifice of medieval theology. Remove it, and one removed the need for the priesthood and the medieval institutional church as it then existed.
...Hus was tried by the Catholic Church for heresy. Finding him guilty, the State's charges against him were allowed to proceed.
So why did the State execute him? The Church recorded their contradiction of his heresies as part of the Council of Constance (and yes, the leaders of the Orthodox churches present concurred.) But I do not find the State's case. My guess, however, is that article 30 was found to be treasonous:
This does not seem accurate, again from the other sources I've looked at so far. By all accounts he was tried by the Church, not the State, and he was executed by the State because the Church turned him over to the secular authorities for execution.
Once in Constance, Hus was lured into the papal residence, then imprisoned in a Dominican dungeon. What followed were months of interrogation and suffering. Zygmunt withdrew his safe conduct in January 1415. It was only due to great pressure exerted by Bohemian noblemen that Hus was given any semblance of a public hearing on June 5, 7, and 8, but he was not allowed to respond to the charges made against him. Presented with a list of 30 articles allegedly drawn from his writings but in fact drawn from the writings of John Wycliffe, Hus was ordered to renounce them upon oath. He refused, unless instructed from Scripture as to where his teachings were in error. The Council rejected his appeal to the Bible as a superior authority.On July 6, Hus was given a final opportunity to recant. Again he refused, saying that since he did not hold all of the views as stated, to recant would be to commit perjury. He was then declared an arch-heretic and a disciple of Wycliffe. He was ceremoniously degraded from the priest-hood, his soul was consigned to the devil, and he was turned over to the secular authorities for execution. That same day, he was led to a meadow outside the city wall and burned alive.
http://biography.yourdictionary.com/jan-hus
Cordially,