Nicea II, 7th Ecumenical Council 787 a.d.
ANATHEMA to those who spurn the teachings of the holy Fathers and the tradition of the 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. (Session I)