Published: 08.09.2021.
First Letter of St. Clement to the Corinthians
“And we have put you in mind of these things the more gladly, since we knew well that we were writing to men who are faithful and highly accounted and have diligently searched into the oracles of the teaching of God. Therefore it is right for us to give heed to so great and so many examples and to submit the neck and occupying the place of obedience to take our side with them that are the leaders of our souls, that ceasing from this foolish dissension we may attain unto the goal which lieth before us in truthfulness, keeping aloof from every fault. For ye will give us great joy and gladness, if ye render obedience unto the things written by us through the Holy Spirit, and root out the unrighteous anger of your jealousy, according to the entreaty which we have made for peace and concord in this letter. And we have also sent faithful and prudent men that have walked among us from youth unto old age unblamably, who shall also be witnesses between you and us.” (62:3-63:3)
(St. Clement was the fourth bishop of Rome from about 88 to 97.) http://www.ntslibrary.com/PDF%20Books/First%20Epistle%20of%20Clement%20to%20the%20Corinthians.pdf
First Epistle of St. Ignatius of Antioch to the Romans
“Ignatius, who is also called Theophorus, to the Church which has obtained mercy, through the majesty of the Most High Father, and Jesus Christ, His only-begotten Son; the Church which is beloved and enlightened by the will of Him that wills all things which are according to the love of Jesus Christ our God, which also presides in the place of the region of the Romans, worthy of God, worthy of honour, worthy of the highest happiness, worthy of praise, worthy of obtaining her every desire, worthy of being deemed holy, and which presides over love, is named from Christ, and from the Father, which I also salute in the name of Jesus Christ, the Son of the Father: to those who are united, both according to the flesh and spirit, to every one of His commandments; who are filled inseparably with the grace of God, and are purified from every strange taint, [I wish] abundance of happiness unblameably, in Jesus Christ our God.” (Preface)
“You have never envied any one; you have taught others.” (Chapter 3)
(This document was written around 107.) https://www.newadvent.org/fathers/0107.htm
St. Iraeneus of Lyons, Against Heresies
“Since, however, it would be very tedious, in such a volume as this, to reckon up the successions of all the Churches, we do put to confusion all those who, in whatever manner, whether by an evil self-pleasing, by vainglory, or by blindness and perverse opinion, assemble in unauthorized meetings; [we do this, I say,] by indicating that tradition derived from the apostles, of the very great, the very ancient, and universally known Church founded and organized at Rome by the two most glorious apostles, Peter and Paul; as also [by pointing out] the faith preached to men, which comes down to our time by means of the successions of the bishops. For it is a matter of necessity that every Church should agree with this Church, on account of its pre- eminent authority, that is, the faithful everywhere, inasmuch as the apostolical tradition has been preserved continuously by those [faithful men] who exist everywhere.” (Third Book, Chapter 3, Paragraph 2, p. 686-687.)
(This was written around the 180s.) https://documentacatholicaomnia.eu/03d/0130-0202,_Iraeneus,_Adversus_haereses_libri_5_%5BSchaff%5D,_EN.pdf, https://www.documentacatholicaomnia.eu/20_30_0130-0202-_Iraeneus.html
Church historian Eusebius, quoting a letter from Dionysius, bishop of Corinth, to Pope Soter
“There is extant also another epistle written by Dionysius to the Romans, and addressed to Soter, who was bishop at that time. We cannot do better than to subjoin some passages from this epistle, in which he commends the practice of the Romans which has been retained down to the persecution in our own days. His words are as follows: “For from the beginning it has been your practice to do good to all the brethren in various ways, and to send contributions to many churches in every city. Thus relieving the want of the needy, and making provision for the brethren in the mines by the gifts which you have sent from the beginning, you Romans keep up the hereditary customs of the Romans, which your blessed bishop Soter has not only maintained, but also added to, furnishing an abundance of supplies to the saints, and encouraging the brethren from abroad with blessed words, as a loving father his children.” p. 385
(Eusebius died in 339.) https://www.documentacatholicaomnia.eu/03d/0265-0339,_Eusebius_Caesariensis,_Historia_ecclesiastica_%5bSchaff%5d,_EN.pdf, https://www.documentacatholicaomnia.eu/20_30_0265-0339-_Eusebius_Caesariensis,_Sanctus.html