The implicit doctrine of Papal infallibility has been operational since the time of Christ. That doctrine became explicitly defined in 1870. The Infallible Council declared Honorius guilty of HERESY! Was the Council in error?
No. The heresy of Honorius was not infallible because it did not meet the requirement of an ex cathedra statement, as I previously demonstrated with the quote from the Catholic Encyclopedia.
The Catholic Encyclopedia is no more official Church Teaching than WikiPedia.
Honorius, a Pope, was a HERETIC and taught heresy. So says the Infallible judgment of the First Ecumenical Council.
Ah, the old “Simon Says” of infallibility. Did not meet the requirements of an ex cathedra statement. Just another way of saying “I didn’t say SIMON says. You’re OUT..”