John Wycliffe (c.1330-1384), an Oxford professor, developed a number of doctrines – that the Bible is the supreme authority, that the clergy should hold no property, that there is no basis for the doctrine of transubstantiation – which were later condemned as heretical. Among his greatest contributions to English literature was his inspiration of the translation of the Bible into Middle English, the first complete translation in the language, and a notable influence on the language itself.
Wycliffe's ideas, usually in their more extreme forms, were adopted by the Lollards (see below), a movement that spread rapidly after his death. In his own lifetime, he was strongly supported by his colleagues at Oxford and by powerful laymen, such as John Of Gaunt. His ideas were current among intellectual circles, at least among the so-called "Lollard knights," several of whom were among Chaucer's acquaintances (see The Riverside Chaucer, p. 863, n. 1173, for further explanation and bibliography).
Wycliffe was brought to trial in 1377 (though nothing much came of it, since he was so strongly backed by powerful supporters in the courts of both John of Gaunt and the King), and he and his doctrines were formally condemned in 1382 by Pope Gregory XI, who ordered that he be arrested. But his order was never carried out. Finally in 1382 the Archbishop of Canterbury condemned him and his writings, but Wycliffe himself was undisturbed and continued to write until his death in 1384.
There was little public interest in rooting out heresy and King Richard regularly resisted clerical demands that he establish burning as the punishment for heresy (common on the Continent). Henry IV issued the first order for burnings – De haretico comburendo in 1401, and the hunt for heresy began in earnest a few years later. Wycliffe was finally condemned 41 years after his death: his books were burned and his body was exhumed and burned, with the ashes scattered.
The Lollards were followers of Wycliffe, at first composed of Wycliffe's supporters at Oxford and the royal court, but soon the movement spread and became a strong popular movement. It was blamed (perhaps unfairly) for some of the anticlerical aspects of the Peasant's Revolt. But Lollard beliefs remained among members of Richard's court – some of whom were among Chaucer's friends (see K.B. McFarlane, Lancastrian Kings and Lollard Knights. Oxford. 1972 [Widener Br 1525.127.5]).
For a statement of the Lollards' beliefs, see
The Twelve Conclusions of the Lollards, which were composed for presentation to Parliament (which included some supporters of the Lollards) in 1395.
For a bibliography of scholarly and critical works on Wycilffe and the Lollards, click here.