Heresy in the Middle Ages differed in some respects from the heresy of the earlier years of Christianity. It was less confined to scholars and theologians; it originated among the people, who--poor, oppressed, and helpless--turned in vain to the Church for assistance. And, instead of being concerned with subtle points of theology, it was inspired mainly by the iniquities of the ecclesiastical order. Simple men felt, by a wholesome instinct, that an immoral life was inconsistent with the function of leading them in the way of righteousness, and some of these simple men began to inquire whether everything taught by the priesthood was really true. This was one of the reasons why the lives of heretics were generally purer than the lives of their oppressors. The mighty of this world persecuted the heretic; the secular courts were severe, the ecclesiastical tribunals were severer still; the main stream of public opinion ran strongly against all innovation in religion. It is not, therefore, to be supposed that the heretic became a voluntary outcast from a love of danger, or for the sake of enjoying the pleasures of sin for a season. The highest authorities in the Church admitted that heresy was caused, though not justified, by the scandalous lives of her ministers. When slaying heretics the Church should have remembered that the chief culprit was herself. Sharp controversies as to the efficacy of the Mass arose about the middle of the eleventh century, and on this subject the Church showed some vacillation. Its official doctrine was that the virtue of the sacrament did not depend upon that of the ministrant. The contrary was, however, asserted by Pope Nicholas II, and the Synod of Rome adopted a canon forbidding any one to be present at a mass celebrated by a priest known to be of loose morals. Gregory VII’s revival of this canon produced great confusion, for virtuous priests were rare exceptions. Against the official views the heretics consistently protested, but hundreds of years elapsed before the professions and the conduct of the clergy were brought into something like agreement.