The Early Church Fathers on various topics: This was a 3700 hour project which included going through 22896 pages of the 38 volume set called Ante Nicene, Nicene, Post Nicene Fathers. I compiled 255 pages of quotes showing that the Early Church was always and completely Catholic. All of these quotes can be verified and found from the source which is free online.
Cyprian of Carthage epistle 2 par 1 (200-270 ad)
We have been informed by Crementius the sub-deacon, who came to us from you, that the blessed father Cyprian has for a certain reason withdrawn; "in doing which he acted quite rightly, because he is a person of eminence, and because a conflict is impending," which God has allowed in the world, for the sake of cooperating with His servants in their struggle against the adversary
Cyril of Jerusalem Catechetical Lecture 7 par 9 (315-386 ad)
And that thou mayest learn more exactly that in the Divine Scriptures it is not by any means the natural father only that is called father, hear what Paul says:--For though ye should have ten thousand tutors in Christ, yet have ye not many fathers: for in Christ Jesus I begat you through the Gospel. For Paul was father of the Corinthians, not by having begotten them after the flesh, but by having taught and begotten them again after the Spirit.
John Cassian Institutes Book 2 ch 3 (360-435 ad)
And so throughout the whole of Egypt and the Thebaid, where monasteries are not rounded at the fancy of every man who renounces the world, but through a succession of fathers and their traditions last even to the present day, or are rounded so to last, in these we have noticed that a prescribed system of prayers is observed in their evening assemblies and nocturnal vigils.
John Cassian Conference 1 ch 1 (360-435 ad)
WHEN I was in the desert of Scete, where are the most excellent monastic fathers and where all perfection flourishes, in company with the holy father Germanus (who had since the earliest days and commencement of our spiritual service been my closest companion both in the coenobium and in the desert
Augustine Letter from Jerome to Augustine (354-430 ad)
To his holy lord and most blessed father, Augustine, Jerome sends greetings.
Augustine Letter 209 (354-430 ad)
To Caelestine, my lord most blessed, and holy father venerated with all due affection, Augustine sends greetings in the Lord
1. First of all I congratulate you that our Lord God has, as we have heard, established you in the illustrious chair which you occupy without any division among His people. (Caelestine was made pope in 422 Augustine is writing in 423)
Gregory the Great Letters Book 14 letter 16 (540-604 ad)
To the most blessed and honourable lord, the holy father Pope Gregory, Felix lover of your Weal and Holiness.
Venerable Bede Ecclesiastical History of England Book 4 ch 32 (672-735 ad)
The brother having long laboured under this malady, when no human means availed to save his eye, but rather, it grew daily worse, on a sudden, through the grace of the mercy of God, it came to pass that he was cured by the relics of the holy father, Cuthbert. For when the brethren found his body uncorrupted, after having been many years buried, they took some part of the hair, to give, as relics, to friends who asked for them, or to show, in testimony of the miracle.