as Caesar under Macrinus AD 217 - 218
as Augustus AD 218
Marcus Opellius Antoninus Diadumenianus (earlier Marcus Opellius Diadumenianus) (AD 208 - 218), Son of Macrinus.
AD 217 - 218 - Caesar under Macrinus
AD 218 - co-Emperor with Macrinus
Briefly reigning as co-Augustus, in 217-128, Diadumenian was elevated by his father Marcinus. Both had ill luck with their soldiers and were murdered after a few months.
List all Diadumenian coins in the Catalog.