Epistle of Ignatius to the Smyrnaeans
"Chapter VIII.-Let Nothing Be Done Without the Bishop.
See that ye all follow the bishop, even as Jesus Christ does the Father, and the presbytery as ye would the apostles; and reverence the deacons, as being the institution of God. Let no man do anything connected with the Church without the bishop. Let that be deemed a proper Eucharist, which is [administered] either by the bishop, or by one to whom he has entrusted it.
Wherever the bishop shall appear, there let the multitude [of the people] also be; even as, wherever Jesus Christ is,
there is the Catholic Church. It is not lawful without the bishop either to baptize or to celebrate a love-feast; but whatsoever he shall approve of, that is also pleasing to God, so that everything that is done may be secure and valid"
Interestingly no one should be called universal bishop. It is a remnant of the earlier church teaching about no one assuming almighty offices. But the Church in Rome has already by this time moved further away from the primitive church. It is a stepping-stone/phase in the development of the Papacy.
Compare this with
http://en.wikipedia.org/wiki/Bishop_of_Rome
The Catholic argument is
"Gregory the Great condemned the title universal bishop in the sense of meaning that all other bishops are not really bishops, but mere agents of the one Bishop, a concept that is blatantly contrary to Catholic teaching, which holds that all bishops are by divine institution true successors of the Apostles. For he states:
For if one, as he supposes, is universal bishop, it remains that you are not bishops.
{Epistle LXVIII}"
http://ic.net/~erasmus/RAZ152.HTM
Which is in fact contrasted by Catholic teaching that makes the bishop of Rome more equal than all others, and that all others are dependent on their office to him.
Compare the early church with this. A bishop is supreme in his diocese. No one above him but Jesus. In the RC Church every bishop however can be undermined by one bishop, that of the bishop of Rome.
It's a legal fiction that the RC Church maintains in order to pretend its bishops are the same; the idea lampooned in another and un-related work "Some are more equal than others".*
936 The Lord made St. Peter the visible foundation of his Church. He entrusted the keys of the Church to him. The bishop of the Church of Rome, successor to St. Peter, is "head of the college of bishops, the Vicar of Christ and Pastor of the universal Church on earth" (CIC, can. 331).
http://www.scborromeo.org/ccc/para/936.htm
There's only one "Vicar of Christ" and only one "Pastor" of the universal church. It's simply playing with words; universal bishop or universal pastor.
882 The Pope, Bishop of Rome and Peter's successor, "is the perpetual and visible source and foundation of the unity both of the bishops and of the whole company of the faithful." "For the Roman Pontiff, by reason of his office as Vicar of Christ, and as pastor of the entire Church has full, supreme, and universal power over the whole Church, a power which he can always exercise unhindered."
http://www.scborromeo.org/ccc/para/882.htm