Was there just one Catholic Church from the 1st century to the 5th century? **I am told no by some. **
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; even as, wherever Jesus Christ is, there is the Catholic Church." Ignatius of Antioch, student of John the Apostle Epistle to the Smyrneans, 8:2 (c. A.D. 110).
When finally he concluded his prayer, after remembering all who had at any time come his way – small folk and great folk, distinguished and undistinguished, and the whole Catholic Church throughout the world… (The Martyrdom of Polycarp 8 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).
The Catholic Church possesses one and the same faith throughout the whole world, as we have already said (Irenaeus Against Heresies 1:10 A.D. 189]).
Where was Marcion then, that shipmaster of Pontus, the zealous student of Stoicism? Where was Valentinus then, the disciple of Platonism? 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 The Prescription Against Heretics 22,30 A.D.200])
“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…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).
Concerning this Holy Catholic Church Paul writes to Timothy, ‘That thou mayest know haw thou oughtest to behave thyself in the House of God, which is the Church of the Living God, the pillar and ground of the truth’” Cyril of Jerusalem, Catechetical Lectures,18:25(A.D. 350).
“And in the Holy Spirit, the Lord, the life-giver, Who proceeds from the Father, Who with the Father and the Son is together worshiped and together glorified, Who spoke through the prophets; in one holy Catholic, and apostolic Church.” Constantinopolitan Creed (A.D. 381).
“Those who from heresy turn to orthodoxy, and to the portion of those who are being saved, we receive according to the following method and custom: Arians, and Macedonians, and Sabbatians, and Novatians, who call themselves Cathari or Aristori, and Quarto-decimans or Tetradites, and Apollinarians, we receive, upon their giving a written renunciation [of their errors] and anathematize every heresy which is not in accordance with the Holy, Catholic, and Apostolic Church of God.” Council of Constantinople I, Canon 7 (A.D. 381).
“We must hold to the Christian religion and to communication in her Church, which is Catholic and which is called Catholic not only by her own members but even by all her enemies. For when heretics or the adherents of schisms talk about her, not among themselves but with strangers, willy-nilly they call her nothing else but Catholic. For they will not be understood unless they distinguish her by this name which the whole world employs in her regard.” Augustine, The True Religion, 7:12 (A.D. 390).
“Wherefore the most holy and blessed Leo, archbishop of the great and elder Rome, through us, and through this present most holy synod together with the thrice blessed and all-glorious Peter the Apostle, who is the rock and foundation of the Catholic Church, and the foundation of the orthodox faith…” Council of Chalcedon, Session III (A.D. 451).