Soon after all of the patriarchal sees were established, the idea of Rome being the “first among equals” was starting to be argued by Roman Pontiffs. These Popes would all build off the idea of the primacy of Peter’s see over all others and from then on argue for Peter’s successors having primacy over all patriarchs. The continued statements of papal primacy and the importance of Rome by several popes after the third century AD would  lead to a major reason of the total split between eastern and western Christianity altogether.

a.) In the letter to Emperor Anastasius I, Pope Gelasius I outlines the relationship of the political realm of the emperor with the spiritual realm of the papacy. In this letter, Pope Gelasius gives two central arguments to show how the papacy in the west was the equal if not the higher of two positions in the christian world. He states this need for mutual respect of authority when he states, “I ask you, ought you to obey those who have been charged with the administering of the sacred mysteries?” (Anderson 60). Here he states that it is an obvious responsibility of the Roman emperors to respect and recognize the authority of the priestly class who deals with the sacred. The second argument that Pope Gelasius uses to illustrate the importance of the papacy in the relationship of the positions is that its is religiously ordained in the scriptures that that the role of leader of the political realm and of the religion be separated.He argues that its a pagan tradition to have both of these positions combined. He states this in the later when he writes “It happened that before the coming of Christ that certain men, though still engaged in the carnal activities, were both kings and priests, and sacred history tells us that Melchizedek was one.” (Anderson 61). Here Gelasius uses historical examples of the combination of kingship and priesthood to show how it wasn’t only pagan but the work of the devil and should be separated altogether.
b.) Pope Leo defend the idea of papal primacy x with three distinct arguments. He states that the apostolic authority of Rome supersedes all others. He states this fact as Rome was the destination of Peter after Jesus ministry. He argues that like Jesus stating that Peter was like a rock, and on that rock he would build the church, Rome is that Rock, the Rock that peter chose to build his church and therefore the site of Peter’s church is primal location of the christian religion. He secondly argues in Col. 995, that although “Constantinople has its own glory” it cannot be held at the level of a true apostolic see as no apostles ever had a mission there. This argument ties into his first point that apostolic missions determine the importance of cities in the christian religion and peter obviously is the head of this order. Lastly, he argues in Col 991 and 1081 that the bishop of Rome is the “guardian of the faith” and the “vicar” (a representative or deputy of a bishop) of St. Peter himself and therefore the head advocate of the Christian religion altogether.
c.) Gregory the great argues that although the other sees have an important role to play in the christian religion, Rome is the seat of the “Prince of the apostles” Saint Peter and that “he sits on it in the persons of his successors (Anderson 61). Here, as he stated in his letters to Pepin III, he is stating that the successors of Peter, i.e all the later bishops of Rome, are the embodiment of Peter himself and that intrinsically gives the seat of the bishop of Rome more spiritual authority. This more openly than his fellow bishops and popes states the idea of Papal primacy being held by the bishop of Rome, as he supposedly is Peter himself. There isn’t any greater claim that a Pope could make that solidifies his position as the first among equals in Christendom altogether.
d.) The Donation of Constantine, although a forgery, was an important document used by the western church to to solidify its claims to authority in the west. The document essentially states that after Constantine was baptized and apparently “cured” of leprosy, he recognized the holiness of the trinity of God and the spiritual power that God gave to “Who shall sit on the chair of blessed Peter to the end of time.” ( Anderson 59). He quotes Matthew 16:8 and uses the biblical narrative of Jesus giving Peter the “keys to the kingdom” and makes this analogous to his giving the keys to Christendom to the Roman Pontiff.  He goes on to expound the importance of the see of saint peter and thereby gives Pope Sylvester and all his successors who sit on the throne of Saint Peter, primacy over all other sees. This latter half of the letter is where the false nature of the letter comes into the light, as the emperor names of all the sees and states that the Roman pontiff has absolute authority over all other sees, something clearly not in the tradition of the church at that point.