For in as many days as this world was made, in so many thousand years shall it be concluded. And for this reason the Scripture says: "Thus the heaven and the earth were finished, and all their adornment. And God brought to a conclusion upon the sixth day the works that He had made; and God rested upon the seventh day from all His works." This is an account of the things formerly created, as also it is a prophecy of what is to come. For the day of the Lord is as a thousand years; and in six days created things were completed: it is evident, therefore, that they will come to an end at the sixth thousand year. Irenaeus (A.D. 180) Ante-Nicene Fathers vol.1 pg.557

So that even from these writings Moses and his followers are proved to be 900 or even 100 years prior to the Trojan war…Then concerning the building of the temple in Judaea, which Solomon the king built 566 years after the exodus of the Jews from Egypt, there is among the Tyrians a record how the temple was built; and in their archives writings have been preserved, in which the temple is proved to have existed 143 years 8 months before the Tyrians founded Carthage. Theophilus (A.D. 180) Ante-Nicene Fathers vol.2 pg.117

During Noah's life, in his 600th year, the flood came. The total number of years, therefore, till the flood, was 2242. Theophilus (A.D. 180) Ante-Nicene Fathers vol.2 pg.118

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…All the years from the creation of the world amount to a total of 5698 years, and the odd months and days…And perhaps our knowledge of the whole number of the years is not quite accurate, because the odd months and days are not set down in the sacred books. Theophilus (A.D. 180) Ante-Nicene Fathers vol.2 pg.120-121

Besides, Eupolemus, in a similar work, says that all the years from Adam to the fifth year of Ptolemy Demetrius, who reigned twelve years in Egypt, when added, amount to five thousand a hundred and forty-nine; and from the time that Moses brought out the Jews from Egypt to the above-mentioned date, there are, in all, two thousand five hundred and eighty years. And from this time till the consulship in Rome of Caius Domitian and Casian, a hundred and twenty years are computed. Clement of Alexandria (A.D. 195) Ante-Nicene Fathers vol.2 pg.332

From Adam to the death of Commodus, five thousand seven hundred and eighty-four years, two months, twelve days. Clement of Alexandria (A.D. 195) Ante-Nicene Fathers vol.2 pg.333

The whole Jewish nation was overthrown within one single generation after Jesus had undergone these sufferings at their hands. For forty and two years, I think, after the date of the crucifixion of Jesus, did the destruction of Jerusalem take place. Now it has never been recorded, since the Jewish nation began to exist, that they have been expelled for so long a period from their venerable temple-worship and service, and enslaved by more powerful nations. Origen (A.D. 248) Ante-Nicene Fathers vol.4 pg. 506

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 "shall reign with Christ," when He comes from heaven, as John says 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." In mentioning the "other," moreover, he specifies the seventh, in which there is rest. Hippolytus (A.D. 225) Ante-Nicene Fathers vol.5 pg.

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. All kinds of temptation, and arts, and snares for his overthrow, he has learned by the very practice of long years. Cyprian (A.D. 250) Ante-Nicene Fathers vol.5 pg. 496

At the seventh thousand years, when God shall have completed the world, He shall rejoice in us. Methodius (A.D. 311) Ante-Nicene Fathers vol.6 pg. 344

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 (A.D. 311) Ante-Nicene Fathers vol.6 pg. 381