Are these the end times? When will Christ return?

Didache c. 100 ADDidache 16.1

Watch over your life. Let your lamps not go out, nor your loins be ungirded, but be ready; for you do not know the hour in which our Lord is coming.

The church manual's last chapter, on the signs of the end.

Hippolytus of Rome c. 170–c. 235 ADCommentary on Daniel 4.23–24

But someone will surely say: How will you prove to me that the Savior was born in the five thousand five hundredth year? ... [the ark's measure of five and a half cubits] shows the five thousand five hundred years.

Hippolytus dates Christ's birth to year 5500 of the world, so the six thousand years end about AD 500. He did it to calm those who said the end was at hand.

Cyprian of Carthage c. 200–258 ADTo Demetrianus 3

You must know first of all that the world has now grown old. It does not stand in the strength it once had, nor is it as vigorous and robust as before. Even if we were silent and brought no proofs from the holy Scriptures, the world itself now says so, and bears witness to its decline by the failing of things.

A pagan blamed Christians for plague and war. Cyprian answers that the world is in its old age.

Lactantius c. 250–c. 325 ADDivine Institutes 7.14.9–10

Since all God's works were finished in six days, the world must remain in this state for six ages, that is, six thousand years. For the great day of God is bounded by a cycle of a thousand years, as the prophet shows, who says: "Before your eyes, Lord, a thousand years are as one day."

Lactantius reckoned that about two hundred years remained (7.25).

Augustine of Hippo 354–430 ADCity of God 18.53.1

Here the question is usually asked: When will this be? Quite out of place. For if it profited us to know, from whom better would it have been told than from God himself, our teacher, when the disciples asked him? ... It is in vain, then, that we try to count and fix the years left to this world, since we hear from the mouth of Truth that it is not for us to know. Yet some have said four hundred, some five hundred, some even a thousand years from the Lord's ascension to his last coming. ... He who says "It is not for you to know the times" loosens the fingers of all who calculate about this, and tells them to rest.

Augustine's answer to every date-setter, ancient and modern.