That's the paradox. For the more ancient culture is the more advanced.
7 seconds sound clip from the Planet of the Apes (1968) movie soundboard.
You can hear this line at 01:35:26 in the Blu-ray version of the movie.
Quote context
[...]
- Present your evidence, Cornelius.
- It was at this level that I discovered traces of an early ape creature...
- A stage of primitive barbarism, really, dating back some 1300 years, roughly.
- But the artifacts lying here were found at this level and date back, uh, 700 years earlier.
- That's the paradox. For the more ancient culture is the more advanced.
- Now, admittedly, many of these objects are unidentified.
- But clearly, they were fashioned by beings with a knowledge of metallurgy.
- Some of the evidence is uncontestable.
[...]