"Monetae cudendae ratio" (also spelled "Monetæ cudendæ ratio"; English: "On the Minting of Coin" or "On the Striking of Coin"; sometimes, "Treatise on Money") is a paper on coinage by Nicolaus Copernicus (Polish: Mikołaj Kopernik). It was written in 1526 at the request of Sigismund I the Old, King of Poland, and presented to the Prussian Diet.