Marcus Opellius Antoninus Diadumenianus or Diadumenian (died 218) was the son of Roman Emperor Macrinus, who served his father briefly as Caesar from May, 217 to 218, and as Augustus in 218. His mother was Empress Nonia Celsa, although her existence remains dubious, because she was only mentioned by the Historia Augusta. He was born Marcus Opellius Diadumenianus, but his name was changed and added Antoninus to solidify connection to the family of Marcus Aurelius as done by Caracalla. Diadumenia… (More on Diadumenianus)