Medo-Persian Kingdom: Laws of, Unalterable

So they approached the king and asked about his royal decree: “Did you not sign a decree that for thirty days any man who petitions any god or man except you, O king, will be thrown into the den of lions?” The king replied, “According to the law of the Medes and Persians the order stands, and it cannot be repealed.”

Then the men approached the king together and said to him, “Remember, O king, that by the law of the Medes and Persians no decree or ordinance established by the king can be changed.”