 Macrinus was overthrown at the Battle of Antioch on 8 June 218 and Elagabalus proclaimed himself emperor with support from the rebelling Roman legions.Macrinus fled the battlefield and tried to reach Rome, but was captured in Chalcedon and later executed in Cappadocia.He sent his son to the care of Artabanus V of Parthia, but Diadumenianus was also captured before he could reach his destination and executed.