Don't forget, though, that the hotbed of heresy was the East. Monophytism, Nestorianism, Arianism, etc. were all popular in the East. Regional Synods were convened to remove bishops who favored orthodoxy. Saint Athanasius was exiled by such a Synod. The Bishop of Rome, however, remained a bullwark against heresy. Hersiarchs such as Nestor and Arius thought his opinion so authoritative that they often appealed directly to the Bishop of Rome to accept their doctrines despite the fact that they held huge popular sway in the East, particularly among the emperors. There was an unwholesome blending of empire and Church in the East that caused the bishops to be very much subject to the emperor/empress. This simply did not happen in the West.
This is an interesting post...Benedict XVI certainly has a an ecumenical zeal that is truly admirable.
I wonder about something.
I work for a Protestant organization that has relationships with other organizations that could be called "Partial Communion" I wonder if a degree of "Partial Commnunion" could be achieved in the short term, such as the Orthodox Churches adopting a view towards the Sacraments similar to the view the Vatican holds towards Orthodox Sacraments.
Which would basically (as I understand it) recognize them as valid should a need arise that would keep a Communicant from fulfilling his obligations within his own rite.
Such as a Catholic traveling in Russia or Greece might need to go to an Orthodox Church because no Catholic Church was available and vise versa.
And the Orthodox of the East did appreciate the orthodoxy of the Bishop of Rome. The one heresy that the west had to struggle with was Pelagianism.
Borgia Popes, anyone? ;-)