Some Anabaptists of the Radical Reformation believe that the Church became corrupt when Constantine I ended the persecution of Christians with the Edict of Milan, and was not recovered until the Anabaptists came along. Others set other dates or time periods when the Church corrupted itself, making it necessary for them to leave the Roman Catholic Church in order to re-establish the true Church. Several descendant groups, including Baptists and Mennonites, believe that besides the Great Apostasy there has also always been a "little flock", a "narrow way" which struggled through persecution and remained faithful to the truth. For example, the Mennonites published a book called the "Martyrs Mirror" in 1660 that attempted to show that exclusive Believer's baptism was practiced and passed down in every century, and how those who held that belief were persecuted for it. Some groups held that the Apostasy of the Roman Catholic Church was so complete as to nullify its claims to Christianity. Consequently, in these groups, repudiation of the ecumenical councils has followed, in a few minority cases engendering seventh-day Sabbatarianism and unitarianism, along with believers baptism and pacifism and other anti-traditional views.