What is the law of the medes and Persians?

The law of the Medes and Persians refers to a legal principle from the ancient Persian Empire, which stated that once a decree or law was established, it could not be altered or repealed. This concept is notably mentioned in the Book of Daniel in The Bible, illustrating the absolute nature of the decrees issued by Persian kings. It emphasizes the permanence and unchangeability of laws in that society, reflecting the authority of the monarch and the legal system of the time.