French king Louis XIV had an infamous prisoner with no name—and a mask covering his face. Some reports claim he was forced to wear it. Although the prisoner died and was buried in the Saint-Paul Cemetery in Paris in 1703, his unknown identity sparked countless theories, tall tales, and artwork. In fact, his mask likely wasn’t made of iron at all, but became a popular myth thanks to writings by Voltaire and Alexandre Dumas, History.com reports. Historians do agree that the man did exist. He was probably really wearing a black velvet mask to keep his identity a secret when moving him in or outside of the prison, according to National Geographic. People believe the man could have been anyone from a nobleman or a failed assassin, to even the twin brother of Louis XIV.