This is part of 14th century church history. At this point, there are at least two popes, and mystics are trying to reform the faith from within the church. Pretty soon, other upstarts began to cause ripples that will change the world two centuries later.
John Wycliffe lived in England. The English did not like the idea of the pope living in France because France was their enemy. They did not want to send money to Avignon. They passed the Statute of Praemunire in 1353 forbidding court cases to go out of England.
Wycliffe studied at Oxford and had a goal of eliminating immoral clergymen from the church. In Of Civil Dominion, Wycliffe emphasized that God gave church leadership to use and posses, but not to own. Leaders are only stewards, and God is still God. Also fed up with the Great Schism, Wycliffe bravely attached the pope's authority in 1379. While the pope claimed to be the Church's head, the authority still belongs to Jesus and no one else. The Bible is the sole authority for the believer, and not church tradition. Church tradition should patter itself after the Bible.
With his beliefs, John Wycliffe began to translate the Bible into English. He wanted the people to no longer be starved of God's Word. He even went as far as attacking the doctrine of transubstantiation because priests were withholding the elements of Eucharist from the people. The people were getting no access to Christ whatsoever. He made it known his beliefs that Christ is in charge of the church and the leaders are his housekeepers. They are not Christ himself. Christ's presence is in both the Scriptures and in the bread and wine. The bread and wine cannot be destroyed by being taken by a less-than-holy person.
He had a group at Oxford called the Lollards who would preach and spread his ideas over England. London condemned his views in 1382, making Lollard ideas a capital crime. However, Wycliffe was not martyred before he died. He died a peaceful death.
Oxford soon formed ties with the school in Bohemia, and students could learn for free. Lollard ideas traveled to Prague and influenced Jan Hus. Bohemia also wanted to be free from mixing their civil cases in with church canon. Hus took Wycliffe's ideas and began to reform his country. He would show pictures of people in line to kiss the pope's foot while in another picture, Christ is stripped down and on the cross or washing his disciples' feet. Why is the pope getting honor that Christ didn't even demand?
Once again, Rome did not care for these teachings. They made Hus stand trial at the Council of Constance, promising him safe passage. Hus refused to recant his ideas. The Council decided they don't need to keep promises to heretics, so Jan Hus burned at the stake. As he died, Hus prophesied that the church may have cooked his goose (Hus means "goose"), but a swan would rise to take his place. This was fulfilled in Martin Luther who heard the story and decided that he was the swan. Naturally, banned ideas are going to spread like wildfire and eventually go nuclear.