Answer:
Oxford University professor John Wycliffe (1330-1384) made harsh criticism of Catholic clergy in the fourteenth century. He was a parish priest in Lutterworth, Yorkshire, England, and was also an employee of the English king, having a great influence on him, especially when it came to mediation with the clergy.
Wycliffe was among the first to denounce corruption in the Catholic clergy and to announce the thesis (which would later be widely defended by Luther) that anyone who had faith could have eternal salvation without necessarily having to devote himself to cultivating virtues and to good works. Another of his criticisms, more than theological bias, targeted the Catholic doctrine of the transubstantiation of Christ in the Eucharistic ritual, that is, in the Eucharistic ceremony of bread and wine.
Another important point of Wycliffe's criticism was the defense of the “supreme authority” of Scripture and the non-interference of papal opinion about them and Christian tradition. This principle attacked the pope's authority as representative of Peter on earth and bearer of the "key of the Church." Wycliffe even qualified some popes as antichrists because of this.
One of his main treatises was De veritate Sacrae Scripturae, published in 1378. For Wycliffe, unlike the pope, the scriptures were infallible. This thesis influenced both Lutheranism and Calvinism and its ramifications. One of Wycliffe's last actions was to try to translate the Bible into English, as Luther would, by translating the Bible into German in the sixteenth century.