The Catholic Church has always held the episcopacy derives from the Apostolic See of Rome, that the Apostolic succession and the Petrine succession are inseparable. It means bishops who deliberately secede from the Roman Pontiff immediately lose all authority, and all orthodox bishops must look to the Apostolic See as the source and origin of their episcopal authority and restore that communion if it has at any time been broken. The eminent liturgist Dom Prosper Gueranger proves this extensively from the teaching of the earliest Roman Pontiffs and other orthodox Saints, he writes "St. Leo the Great : "If our Lord willed that there should be something common to Peter and the rest of the princes of His Church, it was only on this condition, that whatsoever He gave to the rest, He gave it to them through Peter." ... This same doctrine is clearly stated in a letter written to Pope St. Symmachus by St. Cesarius of Arles, who lived in the fifth century: "The episcopate flows from the blessed Apostle Peter; and consequently, it belongs to Your Holiness to prescribe to the several Churches the rules which they are to follow." This fundamental principle, which St. Leo the Great has so ably and eloquently developed, this principle, which is taught us by universal Tradition, is laid down with all possible precision in the magnificent letters, still extant, of Pope St. Innocent I., who preceded St. Leo by several years. Thus he writes to the Council of Carthage, that "the episcopate, with all its authority, emanates from the Apostolic See"; to the Council of Milevis, that "bishops must look upon Peter as the source whence both their name and their dignity are derived"; to St. Victricius, bishop of Rouen, that "the Apostolate and the episcopate both owe their origin to Peter."
In the Ecumenical Council of Ephesus, Philip the presbyter said, "There is no doubt, and in fact it has been known in all ages, that the holy and most blessed Peter, prince and head of the Apostles, pillar of the faith, and foundation of the Catholic Church, received the keys of the kingdom from our Lord Jesus Christ, the Saviour and Redeemer of the human race, and that to him was given the power of loosing and binding sins: who down even to to-day and forever both lives and judges in his successors. The holy and most blessed Pope Celestine, according to due order, is his successor and holds his place.". For witnesses from Constantinople in particular, to omit those such as St. Maximus and St. Nicephorus, St. Theodore plainly bears witness to this headship, this power of judging and teaching that the Successor of Peter holds by divine right, writing to St. Leo III, "Since to great Peter Christ our Lord gave the office of Chief Shepherd after entrusting him with the keys of the Kingdom of Heaven, to Peter or his successor must of necessity every novelty in the Catholic Church be referred. Save us, oh most divine Head of Heads, Chief Shepherd of the Church of Heaven" and to St. Paschal I, "Hear, O Apostolic Head, divinely-appointed Shepherd of Christ's sheep, keybearer of the Kingdom of Heaven, Rock of the Faith upon whom the Catholic Church is built. For Peter art thou, who adornest and governest the Chair of Peter."
And on the weight of this unimpeachable Tradition, the Church justly holds, as Brunsmann says, "In order to be able to distinguish with certainty the true Church of Christ from all false claimants, it is sufficient to establish the Apostolic Succession with regard to the primacy of Peter. For, since the primacy is the crown of the Apostolate, the Church which possesses the primacy must needs be Apostolic ... Hence that Church, and that Church only, which can trace its rulers to the first primate, namely, St. Peter, is in fact and by right Apostolic in every sense. Those regional Churches which are subject to the successor of St. Peter, and live in community with him, participate in this Apostolicity. All others, be it that they have separated from the one only Apostolic Church or developed independently of her, lack the note of Apostolicity and consequently cannot be the true Church of Christ.
Any other method, which separates the episcopate from the Apostolic See contrary to this Tradition, will not be able to identify the one uniquely Apostolic Church, tracing it to as many different lines as there are different sees in the Church; not understanding that these derive their authority from that supreme Head and therefore are bound to remain in communion with him. How do the Greek Orthodox disprove the Apostolic succession of the Catholic Church, and prove their Church alone retains it in its fullness?