The third-century adolescent Roman emperor miscalled Elagabalus or Heliogabalus was made into myth shortly after his murder. For 1800 years since, scandalous stories relate his alleged depravity, debauchery and bloodthirsty fanaticism as High Priest of a Syrian Sun God. From these, one cannot discern anything demonstrably true about the boy or his reign. This book, drawing on the author's detailed research and publications, investigates what can truly be known about this emperor. Through careful analysis of all sources, including historiography, coins, inscriptions, papyri, sculpture and topography, it shows that there are things of which we can be sure, and others that are likely. Through these we can reassess his reign. We discover a youth, thrust by his handlers into power on false pretences, who creates his own more authentic persona as priest-emperor, but loses the struggle for survival against rivals in his family, who justify his murder with his myth.