A small band of followers attached themselves to Groote and became his fellow workers, thus becoming the first "Brethren of the Common Life" (). The reformer was opposed by many, including the clergy, for his preaching on moral decadence, and in 1383 his license to preach was revoked. Nonetheless, his zeal for purifying the Catholic faith and the morality of its followers won many to his cause. Members of the secular clergy even enrolled themselves in his brotherhood, which, in due course, was approved by the Pope.