Mithras killing the bull ( c. 150 CE; Louvre-Lens) Rock-born Mithras and Mithraic artifacts ( Baths of Diocletian, Rome) Mithraism, also known as the Mithraic mysteries or the Cult of Mithras, was a Roman mystery religion centered on the god Mithras. Although inspired by Iranian worship of the Zoroastrian divinity ( yazata) Mithra, the Roman.