Meaning: Used to describe something in the past that is no longer important or relevant.

Examples:

I know I used to be a bad person – but that’s ancient history.

You’re still angry about that? I thought it was ancient history!

We broke up. She and I are ancient history.

Pop Quiz:

For which remark is “That’s ancient history” an appropriate response?

A.  We’re out of milk! When are you going to buy more?

B.  Socrates was executed by the Athenians in 399 BC.

C.  Why don’t you exercise? You used to be in shape back in high school!

To see the correct answer, click on “Continue reading”:

The correct answer is C. Answer A is referring to the present and to the future. Answer be is literally ancient history and not related to the idiom. Answer is happened in the past, and your response indicates that you don’t like to exercise anymore even though you used to exercise a lot when you were a teenager.

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