text: This man was the second-to-last ruler covered in an 80-book history by Cassius Dio, who lived through this man's reign.
full_question: This man was the second-to-last ruler covered in an 80-book history by Cassius Dio, who lived through this man's reign. A coin minted by this emperor shows a chariot carrying a sacred black stone away from Emesa in Syria, this man's childhood home. This man, who was made emperor by his grandmother Julia Maesa at age fourteen, allegedly married a Vestal Virgin and gained a reputation for extremely decadent acts before his murder and replacement by Alexander Severus four years later. This man took a name from the non-Christian singular deity he forced Romans to worship instead of Jupiter. For 10 points, name this Roman emperor from 218 to 222 CE, a devotee of a unary sun god.
first_sentence: This man was the second-to-last ruler covered in an 80-book history by Cassius Dio, who lived through this man's reign.
raw_answer: Elagabalus [or Heliogabalus; or Marcus Aurelius Antoninus Augustus Elagabalus; do not accept or prompt on "Marcus Aurelius"]