From the interview of St. Mark with Pope Eugenius:
The Councils of the Church have condemned as rebels those who have transgressed against some dogma and have preached thus and fought for this, for which reason also they are called ‘heretics’; and from the beginning the Church has condemned the heresy itself, and only then has it condemned the leaders of the heresy and its defenders. But I have by no means preached my own teaching, nor have I introduced anything new in the Church, nor defended any foreign and false doctrine; but I have held only that teaching which the Church received in perfect form from our Saviour, and in which it has steadfastly remained to this day: the teaching which the Holy Church of Rome, before the schism that occurred between us, possessed no less than our Eastern Church; the teaching which, as holy, you formerly were wont to praise, and often at this very Council you mentioned with respect and honor, and which no one could reproach or dispute. And if I hold it and do not allow myself to depart from it, what Council will subject me to the interdiction to which heretics are subject? What sound and pious mind will act thus with me? For first of all one must condemn the teaching which I hold; but if you acknowledge it as pious and Orthodox, then why am I deserving of punishment?