“It was composed as a possession for all time, not as a showpiece to be heard for the moment.”
The hint
He wrote what he saw, meant it to last for all time, and did not write for applause. Two locks. The mirror and the road back. Either order.
The cipher
HHVMGRD
— Thucydides · History of the Peloponnesian War · c. 400 BCE
Enter this door
Your email to attempt the solve. One win per solver across the run.