Early Church Fathers on Young Earth

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.

Under 6000 years old
Dinosaurs

Josephus Antiquities of the Jews Book 1 preface par 3 (38-100 ad)
Accordingly, I thought it became me both to imitate the generosity of our high priest, and to suppose there might even now be many lovers of learning like the king; for he did not obtain all our writings at that time; but those who were sent to Alexandria as interpreters, gave him only the books of the law, while there were a vast number of other matters in our sacred books. They, indeed, contain in them the history of five thousand years; in which time happened many strange accidents, many chances of war, and great actions of the commanders, and mutations of the form of our government. Upon the whole, a man that will peruse this history, may principally learn from it, that all events succeed well, even to an incredible degree,
Epistle of Barnabas ch 15 (70-90 ad)
"If my sons keep the Sabbath, then will I cause my mercy to rest upon them." The Sabbath is mentioned at the beginning of the creation the seventh day, and rested on it, and sanctified it." Attend, my children, to the meaning of this expression, "He finished in six days." This implieth that the Lord will finish all things in six thousand years, for a day is with Him a thousand years. And He Himself testifieth, saying, in six days, that is, in six thousand years, all things will be finished.
Ireneaus of Lyons Against Heresies Book 5 ch 23 par 2 (120-180 ad)
The Lord, therefore, recapitulating in Himself this day, underwent His sufferings upon the day preceding the Sabbath, that is, the sixth day of the creation, on which day man was created; thus granting him a second creation by means of His passion, which is that Adam to the thousandth year; for since "a day of the Lord is as a thousand years," he did not overstep the thousand years, but died within them, thus bearing out the sentence of his sin.
Theophilus to Autolycus book 3 ch 28 (150-200 ad)
And from the foundation of the world the whole time is thus traced, so far as its main epochs are concerned. From the creation of the world to the deluge were 2242 years. And from the deluge to the time when Abraham our forefather begat a son, 1036 years. And from Isaac, Abraham's son, to the time when the people dwelt with Moses in the desert, 660 years. And from the death of Moses and the rule of Joshua the son of Nun, to the death of the patriarch David, 498 years. And from the death of David and the reign of Solomon to the sojourning of the people in the land of Babylon, 518 years 6 months 10 days. And from the government of Cyrus to the death of the Emperor Aurelius Verus, 744 years. All the years from the creation of the world amount to a total of 5698 years, and the odd months and days.
Clement of Alexandria Stromata book 1 ch 21 (150-215 ad)
From Adam to the deluge are comprised two thousand one hundred and forty-eight years, four days. From Shem to Abraham, a thousand two hundred and fifty years. From Isaac to the division of the land, six hundred and sixteen years. Then from the judges to Samuel, four hundred and sixty-three years, seven months. And after the judges there were five hundred and seventy-two years, six months, ten days of kings.
Clement of Alexandria Stromata book 1 ch 21 (150-215 ad)
In all, from Augustus to Commodus, are two hundred and twenty-two years; and from Adam to the death of Commodus, five thousand seven hundred and eighty-four years, two months, twelve days.
Bardesanes The Book of the laws of various Countries (154-222 ad)
And this," says he, "is one synchronism of them all; that is, the time of one such synchronism of them. So that from hence it appears that to complete too such synchronisms there will be required six thousands of years. Thus :-- 200 revolutions of Saturn, six thousands of years; 500 revolutions of Jupiter, 6 thousands of years; 4 thousand revolutions of Mars, 6 thousands of years; Six thousand revolutions of the Sun, 6 thousands of years." 7 thousand and 200 revolutions of Venus, 6 thousands of years; 12 thousand revolutions of Mercury, 6 thousands of years." 72 thousand revolutions of the Moon, 6 thousands of years." [+] These things did Bardesan thus compute when desiring to show that this world would stand only six thousands of years.
Hipplytus Extant Works and Fragments Exegetical Interpetation of the visions of Daniel and Nebuchadnezzar (170-236 ad)
For the first appearance of our Lord in the flesh took place in Bethlehem, under Augustus, in the year 5500; and He suffered in the thirty-third year. And 6,000 years must needs be accomplished, in order that the Sabbath may come, the rest, the holy day "on which God rested from all His works." For the Sabbath is the type and emblem of the future kingdom of the saints, when they in his Apocalypse: for "a day with the Lord is as a thousand years." Since, then, in six days God made all things, it follows that 6,000 years must be fulfilled. And they are not yet fulfilled, as John says: "five are fallen; one is," that is, the sixth; "the other is not yet come."
Julius Africanus Extant Writing 3 par 1 (160-240 ad)
The Egyptians, indeed, with their boastful notions of their own antiquity, have put forth a sort of account of it by the hand of their astrologers in cycles and myriads of years; which some of those who have had the repute of studying such subjects profoundly have in a summary way called lunar years; and inclining no less than others to the mythical, they think they fall in with the eight or nine thousands of years which the Egyptian priests in Plato falsely reckon up to Solon. [+] (And after some other matter:) [+] For why should I speak of the three myriad years of the Phoenicians, or of the follies of the Chaldeans, their forty-eight myriads? For the Jews, deriving their origin from them as descendants of Abraham, having been taught a modest mind, and one such as becomes men, together with the truth by the spirit of Moses, have handed down to us, by their extant Hebrew histories, the number of 5500 years as the period up to the advent of the Word of salvation, that was announced to the world in the time of the sway of the Caesars.
Origen Against Celsus book 1 ch 19 (185-254 ad)
After these statements, Celsus, from a secret desire to cast discredit upon the Mosaic account of the creation, which teaches that the world is not yet ten thousand years old, but very much under that, while concealing his wish, intimates his agreement with those who hold that the world is uncreated.
Cyprian of Carthage Treatise 11 par 2 (200-270 ad)
It is an ancient adversary and an old enemy with whom we wage our battle: six thousand years are now nearly completed since the devil first attacked man.
Victorinus on the Creation of the World (240-303 ad)
And in Matthew we read, that it is written Isaiah also and the rest of his colleagues broke the Sabbath--that that true and just Sabbath should be observed in the seventh millenary of years. Wherefore to those seven days the Lord attributed to each a thousand years; for thus went the warning: "In Thine eyes, O Lord, a thousand years are as one day." Therefore in the eyes of the Lord each thousand of years is ordained, for I find that the Lord's eyes are seven. Wherefore, as I have narrated, that true Sabbath will be in the seventh millenary of years, when Christ with His elect shall reign.
Eusebius of Caesarea Church History book 3 (285-340 ad)
We have not, therefore, a multitude of books disagreeing and conflicting with one another; but we have only twenty-two, which contain the record of all time and are justly held to be divine. Of these, five are by Moses, and contain the laws and the tradition respecting the origin of man, and continue the history down to his own death. This period embraces nearly three thousand years.
Lactantius Divine Institutes book 7 (290-350 ad)
Therefore, since all the works of God were completed in six days, the world must continue in its present state through six ages, that is, six thousand years. For the great day of God is limited by a circle of a thousand years, as the prophet shows, who says "In Thy sight, O Lord, a thousand years are as one day." And as God laboured during those six days in creating such great works, so His religion and truth must labour during these six thousand years, while wickedness prevails and bears rule. And again, since God, having finished His works, rested the seventh day and blessed it, at the end of the six thousandth year all wickedness must be abolished from the earth, and righteousness reign for a thousand years;
Methodius Extracts From the Work on Things Created par 9 (300 ad)
For when a thousand years are reckoned as one day in the sight of God, and from the creation of the world to His rest is six days, so also to our time, six days are defined, as those say who are clever arithmeticians. Therefore, they say that an age of six thousand years extends from Adam to our time. For they say that the judgment will come on the seventh day, that is in the seventh thousand years.
Commodianus Writings par 35 (300-360 ad)
We shall be immortal when six thousand years are accomplished.
Commodianus Writings par 80 (300-360 ad)
This has pleased Christ, that the dead should rise again, yea, with their bodies; and those, too, whom in this world the fire has burned, when six thousand years are completed, and the world has come to an end.
Ephriam the Syrian Nisibene Hymns (306-373 ad)
Man, O Death, despise thou it not, that image of Adam: which like a seed is committed to earth, till the Resurrection.--2. R. To thee be glory Who didst descend and plunge, after Adam: and draw him out from the depths of Sheol, and bring him into Eden!--3. Death, I marvel at this seed, and at your words: for lo! after five thousand years, it springs not yet.--4.
Gregory of Nyssa Answer to Eunomius’ Second Book (325-386 ad)
If, then, Moses was a Hebrew, and the language of the Hebrews was subsequent to the others, Moses, I say, who was born some thousands of years after the Creation of the world, and who relates the words of God in his own language
John Chrysostom Homily 9 on First Corinthians (347-407 ad)
Five thousand years and more have passed, and death hath not yet been done away, on account of one single sin.
John Chrysostom Homily 10 on the Statues par 5 (347-407 ad)
But the world, though subsisting now five thousand years, and many more, hath suffered nothing of the kind.
Methodius Fragments ch 9
For a thousand years in Thy sight are but as yesterday: seeing that is past as a watch in the night." For when a thousand years are reckoned as one day in the sight of God, and from the creation of the world to His rest is six days, so also to our time, six days are defined, as those say who are clever arithmeticians. Therefore, they say that an age of six thousand years extends from Adam to our time. For they say that the judgment will come on the seventh day, that is in the seventh thousand years.
Methodius The Banquet of the Ten Virgins discourse 9
we are commanded to keep the feast to the Lord, which signifies that, when this world shall be terminated at the seventh thousand years, when God shall have completed the world
Jerome Letter 51 par 6 (347-420 ad)
"And Adam lived two hundred and thirty years, and knew Eve his wife, and she bare him a son in his image and after his likeness, and called his name Seth." And again, in the tenth generation, two thousand two hundred and forty-two years afterwards, God, to vindicate His own image and to show that the grace which He had given to men still continued in them, gives the following commandment: "Flesh ... with the blood thereof shall ye not eat.
Sulpitius Severus Sacred History book 1 ch 2 (363-420 ad)
The world was created by God nearly six thousand years ago, as we shall set forth in the course of this book; although those who have entered upon and published a calculation of the dates, but little agree among themselves. As, however, this disagreement is due either to the will of God or to the fault of antiquity, it ought not to be a matter of censure.
Sulpitius Severus Sacred History book 1 ch 3 (363-420 ad)
Then being sent forth a third time, it returned no more, from which it was understood that the waters had subsided; and Noah accordingly went out from the ark. This was done, as I reckon, two thousand two hundred[1] and forty-two years after the beginning of the world.
Augustine Exposition on Psalm 6 par 1 (354-430 ad)
"Of the eighth," seems here obscure. For the rest of this title is more clear. Now it has seemed to some to intimate the day of judgment, that is, the time of the coming of our Lord, when He will come to judge the quick and dead. Which coming, it is believed, is to be, after reckoning the years from Adam, seven thousand years: so as that seven thousand years should pass as seven days, and afterwards that time arrive as it were the eighth day.
Augustine Sermon 43 par 8 (354-430 ad)
A man makes as it were a calculation with himself: "Lo, so many years have passed since Adam, and the six thousand years are being completed, and then immediately according to the computation of certain expositors, the Day of Judgment will come;" yet these calculations come and pass away, and still the coming of the Bridegroom is delayed, and the virgins who had gone to meet him sleep. And, lo, when He is not looked for, when men are saying, "The six thousand years were waited for, and, Io, they are gone by, how then shall we know when He will come?" He will come at midnight.

Augustine City of God Book 12 ch 10 (354-430 ad)
OF THE FALSENESS OF THE HISTORY WHICH ALLOTS MANY THOUSAND YEARS TO THE WORLD'S PAST.

But they say what they think, not what they know. They are deceived, too, by those highly mendacious documents which profess to give the history of many thousand years, though, reckoning by the sacred writings, we find that not 6000 years have yet passed.
Augustine City of God Book 12 ch 12 (354-430 ad)
As to those who are always asking why man was not created during these countless ages of the infinitely extended past, and came into being so lately that, according to Scripture, less than 6000 years have elapsed since He began to be, I would reply to them regarding the creation of man, just as I replied regarding the origin of the world to those who will not believe that it is not eternal, but had a beginning, which even Plato himself most plainly declares, though some think Iris statement was not consistent with his real opinion. If it offends them that the time that has elapsed since the creation of man is so short, and his years so few according to our authorities, let them take this into consideration, that nothing that has a limit is long, and that all the ages of time being finite, are very little, or indeed nothing at all, when compared to the interminable eternity.
Augustine City of God Book 18 ch 40 (354-430 ad)
ABOUT THE MOST MENDACIOUS VANITY OF THE EGYPTIANS, IN WHICH THEY ASCRIBE TO THEIR. SCIENCE AN ANTIQUITY OF A HUNDRED THOUSAND YEARS.In vain, then, do some babble with most empty presumption, saying that Egypt has understood the reckoning of the stars for more than a hundred thousand years. For in what books have they collected that number who learned letters from Isis their mistress, not much more than two thousand years ago? Varro, who has declared this, is no small authority in history, and it does not disagree with the truth of the divine books. For as it is not yet six thousand years since the first man, who is called Adam, are not those to be ridiculed rather than refuted who try to persuade us of anything regarding a space of time so different from, and contrary to, the ascertained truth?

Augustine Exposition on Psalm 105 par 6 (354-430 ad)
For by howsoever few years a generation is limited, such as in Greek is called genea, whereof the shortest period some have fixed is at fifteen years, after which period man hath the power of generation; what then are those "thousand generations," not only from the time of Abraham, when that promise was made him, unto the New Testament, but from Adam himself down to the end of the world? For who would dare to say that this world should last for 15000 years?
Theodoret of Cyrus Dialogue 1 (393-457 ad)
and we learn this not only from nature, but also from Holy Scripture, for God said, we read, "I will destroy man from the face of the earth," and this he spake of countless multitudes, and when more than two thousand and two hundred years had gone by after Adam, he brought universal destruction on men through the flood
Dinosaurs
Augustine Exposition on Psalm 148 par 7 (354-430 ad)
"Dragons" live about the water, come out from caverns, fly through the air; the air is set in motion by them: "dragons" are a huge kind of living creatures, greater there are not upon the earth.
Sozomen Ecclesial History Book 7 Ch 16 (375-477 ad)
THERE were at this period many other bishops in various parts of the empire highly celebrated for their sanctity and high qualifications, of whom Donatus, bishop of Euroea in Epirus, deserves to be particularly instanced. The inhabitants of the country relate many extraordinary miracles which he performed, of which the most celebrated seems to have been the destruction of a dragon of enormous size. It had stationed itself on the high road, at a place called Chamaegephyrae and devoured sheep, goats, oxen, horses, and men. Donatus came upon this beast, attacked it unarmed, without sword, lance, or javelin; it raised its head, and was about to dash upon him, when Donatus made the sign of the cross with his finger in the air, and spat upon the dragon. The saliva entered its mouth, and it immediately expired. As it lay extended on the earth it did not appear inferior in size to the noted serpents of India. I have been informed that the people of the country yoked eight pair of oxen to transport the body to a neighboring field, where they burnt it,