Acts of Session I
Anathema to those who spurn the teachings of the holy Fathers and the tradition of the holy Catholic Church, taking as a pretext and making their own the arguments of Arius, Nestorius, Eutyches, and Dioscorus, that unless we were evidently taught by the Old and New Testaments, we should not follow the teachings of the holy Fathers and of the holy Ecumenical Synods, and the tradition of the Catholic Church.  (The Council of Nicea 787, Acts of Session I)