Nero's initiation into the mysteries of Mithras is disputed.
Dio Cassius quotes Tiridates I of Armenia addressing Nero during his visit to Rome in 63.
These were his words: 'Master, I am the descendant of Arsaces, brother of the kings Vologaesus and Pacorus, and thy slave. And I have come to thee, my god, to worship thee as I do Mithras. The destiny thou spinnest for me shall be mine; for thou art my Fortune and my Fate.'
—Dio Cassius. Historia Romana, epitome of book 63, 5:2
Mithras was, also, unified with the sun-god Helios, and became known as 'The Great God Helios-Mithras'. Emperor Nero adopted the radiating crown as the symbol of his sovereignty to exemplify the splendour of the rays of the sun, and to show that he was an incarnation of Mithras. He was initiated into the Mithraic religion by the Persian Magi brought to Rome by the King of Armenia.
—Franz Cumont (1902) Les Mystères de Mithra