The First Council of Nicaea, safeguarding the teachings of the Church, already thought it necessary to condemn the Thalia of Arius, while the Third Council of Constantinople and the Second Council of Nicaea condemned other heretical writings and ordered them to be burnt or withdrawn. In the Middle Ages such books were frequently not only condemned, but forbidden to be read or even possessed, and sometimes they were ordered to be burnt, as in the case of the Apologia for Abaelard written by Berengarius of Poitiers…