Diadumenian (208-218) was the son of Emperor Macrinus, and was so named due to being born with a caul that formed a 'diadem'. He was said to have shared his birthday with that of beloved Emperor Antoninus Pius. He at first served his father briefly as Caesar, before being elevated to Augustus and co-emperor in 218. Unfortunately, the ten-year-old co-emperor had little time to enjoy his position or learn from it as the Syrian legions revolted and proclaimed Elagabus as emperor. When Macrinus was defeated and executed in June of 218, Diadumenian's death soon followed.