John Wycliffe was an English priest and a professor at Oxford University in the 14th century. He lived from 1320-1384. Wycliffe taught many things contrary to the beliefs of the church in his day, including the denial of the authority of the pope, predestination, the denial of the necessity of confessing to a priest, among other things. He also advocated poverty, saying that everyone in a state of sin loses all of his rights to property. He said that any church or priest owning property defies Christ, and that the state should take it from them if they refused to let it go. Many of his views were similar to those in the Protestant reformation, which began over a century later.
In England, the anticlerical party in the government took encouragement from Wycliffe, believing that the king would be able to support himself well financially if he took the property of the bishops and the monasteries. But, he got in trouble with several English bishops, and was called to defend his statements. Aside from this, Wycliffe got away with his teachings for the most part due to the ongoing Western Schism, which brought great confusion to the Catholic church. Due to his views on property, the government abandoned support of him during the Great Revolt, which began in June 1381.
The Great Western Schism, which began in 1378, was a source of great confusion and disruption within Christendom. When Pope Gregory XI died, the college of cardinals met to elect a successor. But, the Roman mob protested outside the building where they met, demanding that they elect a Roman, or at least an Italian. The reason for this was that the seat of the papacy had just been moved back to Rome from Avignon, where the Popes were French.
The cardinals heard the disturbance outside, and quickly elected Bartolomeo Prigano, who was not a Roman, but was at least an Italian. Bartolomeo was known for his even temperament, and was expected to bring stability to the position of Pope. Bartolomeo Prigano took the name Urban VI, becoming the new Pope. Urban, however, began acting in a strange manner. He denounced several church officials who came to see him and even struck one one of them.
The cardinals did not know what was going on, suspecting drunkenness, mental illness, or some other reason. They met again, this time electing Clement VII, who took up residence in Avignon. They told Urban to leave, which he refused to do. Now that there were two popes instead of one, Europe became divided between the followers of Urban and the followers of Clement. Different nations supported the two popes, and even fought wars over it. The people were in much confusion as to who was the real pope, and even people who would later become saints were found on both sides. Both men died, but the two rival lines continued, with others succeeding each.
The cardinals decided to resolve this issue by having an ecumenical council at Pisa in 1409. They declared John XXIII as the new pope, and determined that the other two men step down. Both refused, and the problem got worse with three popes: one in Rome, one in Avignon, and another in Pisa. Finally, in the Council of Constance, they got rid of all three men and made Martin V the new pope. The other men who claimed to be pope either lost their support or stepped down, ending the schism in 1415.