Some stopped going to church, while others tried to preserve the old liturgy with the help of sympathetic priests.[246] These formed the basis of today's Traditionalist Catholic groups, which believe that the reforms of Vatican II have gone too far. Liberal Catholics form another dissenting group who feel that the Vatican II reforms did not go far enough. The liberal views of theologians such as Hans Küng and Charles Curran, led to Church withdrawal of their authorization to teach as Catholics.[247] According to Professor Thomas Bokenkotter, most Catholics "accepted the changes more or less gracefully."[246] In 2007, Benedict XVI eased permission for the optional old Mass to be celebrated upon request by the faithful.[248]