Although Lollardy was denounced as a heresy (by the Roman Catholic Church and the early pre-reformation then Roman Catholic Church of England), initially Wycliffe and the Lollards were sheltered by John of Gaunt and other anti-clerical nobility, who may have wanted to use Lollard-advocated clerical reform to acquire new sources of revenue from England's monasteries. The University of Oxford also protected Wycliffe and similar academics on the grounds of academic freedom and, initially, allowed such persons to retain their positions despite their controversial views. Lollards first faced serious persecution after the Peasants' Revolt in 1381. While Wycliffe and other Lollards opposed the revolt, one of the peasants’ leaders, John Ball, preached Lollardy. The royalty and nobility then found Lollardy to be a threat not only to the Church, but to English society in general. The Lollards' small measure of protection evaporated. This change in status was also affected by the 1386 departure of John of Gaunt who left England to pursue the Crown of Castile.