Law of the Medes and the Persians

American  

noun

1. unalterable law.

---

Etymology

Origin of Law of the Medes and the Persians

Middle English word dating back to 1350–1400

Example Sentences

If Daniel be faithful to his God, he will surely disobey this decree; and if the King once signeth it, the law of the Medes and the Persians saith that it cannot be altered.

From Project Gutenberg

Daughter has accepted mother's precepts, regarding them even as the law of the Medes and the Persians, “which altereth not,” 2and if it were not that increased prices and, lately, at least, “food regulations,” have veritably compelled her toward a more wholesome simplicity, the United States would probably be what it was called half a generation ago, “a nation of dyspeptics.”

From Project Gutenberg

But his princes said it could not be done, because, according to the law of the Medes and the Persians, no decree made by the king could be changed.

From Project Gutenberg