Naming Emperor Constantine as the founder of the Catholic Church is an evidence of poor scholarship and gross ignorance of history. Even Protestant writers admit that Constantine is not the founder of the Catholic Church.
The church in Rome was by far the most important church in Christendom: it was situated in the ancient imperial capital of the empire; it had the largest congregation of Christians; and its ROOTS WENT BACK TO PETER AND PAUL, the two greatest saints in the church. (A HANDBOOK OF THE CHRISTIAN FAITH, By: John SCHWARZ, page 153)
John Schwarz is a protestant writer admits that the history of the Catholic Church can be traced back into the time of the apostles Peter and Paul. During the time of Peter and Paul, Emperor Constantine didn’t exist!
At one level, of course, the interpretation of Roman Catholicism is closely related to the interpretation of Christianity as such. For by its own reading of history, Roman Catholicism began with the very beginnings of the Christian movement. (A HISTORY OF CHRISTIANITY, By: Robert A. Guisepi)
Christianity began at 33 A.D when Christ established the Church, and according to this historian the history of the Catholic Church began at the beginning of Christianity itself! At 33 A.D Emperor Constantine was not yet born!
That the Emperor was sincere, and not a dissembler, in regard to his conversion to Christianity, no person can doubt who believes that men’s actions are an index of their real feelings. It is indeed true that Constantine’s life was not such as the precepts of Christianity required; and it is also true that he remained a catechumen all his life, and was received to full membership in the Church, by baptism, only a few days before his death, at Nicomedia. (CONVERSION OF CONSTANTINE: DECLINE OF PAGANISM, By: Johann Lorenz Von Mosheim)
Constantine converted to Christianity 2 days before his death! Why would he convert to Catholicism if he founded it? Clearly Constantine is not the founder of the Catholic Church! If Constantine is not the founder then who is? No other than but JESUS CHRIST HIMSELF.
Aside from this we also have the statement from the early Church Fathers
“See that ye all follow the bishop, even as Christ Jesus does the Father, and the presbytery as ye would the apostles. Do ye also reverence the deacons, as those that carry out the appointment 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 also be; by the bishop, or by one to whom he has entrusted it. Wherever the bishop shall appear, there let the multitude also be; even as, wherever Jesus Christ is, there is the Catholic Church.” Ignatius of Antioch, Epistle to the Smyrneans, 8:2 (c. A.D. 110).
“[A]ll the people wondered that there should be such a difference between the unbelievers and the elect, of whom this most admirable Polycarp was one, having in our own times been an apostolic and prophetic teacher, and bishop of the Catholic Church which is in Smyrna. For every word that went out of his mouth either has been or shall yet be accomplished.” Martyrdom of Polycarp, 16:2 (A.D. 155).
“…to be in honour however with the Catholic Church for the ordering of ecclesiastical discipline…one to the Laodicenes, another to the Alexandrians, both forged in Paul’s name to suit the heresy of Marcion, and several others, which cannot be received into the Catholic Church; for it is not fitting that gall be mixed with honey. The Epistle of Jude no doubt, and the couple bearing the name of John, are accepted by the Catholic Church…But of Arsinous, called also Valentinus, or of Militiades we receive nothing at all.”The fragment of Muratori (A.D. 177).
“[N]or does it consist in this, that he should again falsely imagine, as being above this [fancied being], a Pleroma at one time supposed to contain thirty, and at another time an innumerable tribe of Aeons, as these teachers who are destitute of truly divine wisdom maintain; while the Catholic Church possesses one and the same faith throughout the whole world, as we have already said.”Irenaeus, Against Heresies, 1:10,3 (A.D. 180).
“For it is evident that those men lived not so long ago,–in the reign of Antoninus for the most part,–and that they at first were believers in the doctrine of the Catholic Church, in the church of Rome under the episcopate of the blessed Eleutherus, until on account of their ever restless curiosity, with which they even infected the brethren, they were more than once expelled.”Tertullian, On the Prescription Against Heretics, 22,30 (A.D. 200).
”Whence you ought to know that the bishop is in the Church, and the Church in the bishop; and if any one be not with the bishop, that he is not in the Church, and that those flatter themselves in vain who creep in, not having peace with God’s priests, and think that they communicate secretly with some; while the Church, which is Catholic and one, is not cut nor divided, but is indeed connected and bound together by the cement of priests who cohere with one another.” Cyprian, To Florentius, Epistle 66/67(A.D. 254).
“But for those who say, There was when He was not, and, Before being born He was not, and that He came into existence out of nothing, or who assert that the Son of God is of a different hypostasis or substance…these the Catholic and apostolic Church anathematizes.” Creed of Nicea (A.D. 325).
“Concerning those who call themselves Cathari, if they come over to the Catholic and Apostolic Church, the great and holy Synod decrees that they who are ordained shall continue as they are in the clergy. But it is before all things necessary that they should profess in writing that they will observe and follow the dogmas of the Catholic and Apostolic Church; in particular that they will communicate with persons who have been twice married, and with those who having lapsed in persecution have had a period [of penance] laid upon them, and a time [of restoration] fixed so that in all things they will follow the dogmas of the Catholic Church…”Council of Nicaea I (A.D. 325).
The preponderance of evidence dismisses the claim of Protestants that the Catholic Church was founded by Emperor Constantine. What the evidences tell us is that Jesus Christ personally and historically founded the Catholic Church. This is a fact of history that no Protestants would want to admit.