However, on 8 April 217, Caracalla fell victim to a plot by his praetorian prefect, Marcus Opellius Macrinus and was murdered.[6] Macrinus became emperor, but already Artabanus was approaching, having gathered a large army in order to avenge himself for the Romans' treacherous attack. The situation was summed up well by Macrinus himself in the speech he delivered to his army, as delivered by Herodian: