The followers of John Wyclif (1324-84), who flourished in England in the fourteenth and fifteenth centuries, although the name was applied to certain heretics in Flanders before its use in England. The principal anti-Catholic positions of the Lollards were denial of the Church's authority and transubstantiation. They also espoused the theory of dominium, which claimed that the validity of the sacraments depends upon the worthiness of the one who administers them. These ideas were spread by Wyclif's "Poor Priests," whose austerity was in marked contrast to the growing luxury of the clergy. Stern measures were taken by the Church and State against the Lollards, who were, in a sense, forerunners of the Reformation in England.