A member of the equestrian class, he is the first emperor not to come from the senatorial class and the first emperor from Mauretania. Before becoming emperor, Macrinus served under Caracalla as praetorian prefect and dealt with civil affairs in Rome. He then conspires against him and has him murdered in an effort to protect his own life, succeeding him as emperor. Macrinus succeeds where Sejanus failed under Tiberius and Plautian under Septimius Severus: he is the first knight to accede to the imperial throne.
Proclaimed Roman Emperor on April 11, 217 in the eastern provinces of the Empire, Macrinus was subsequently confirmed by the Senate. However, during his reign he never had the opportunity to return to Rome. The policies of his predecessor had left the coffers of Rome empty and the Empire at war with several kingdoms, including the Parthians, Armenia and Dacia. As emperor, Macrinus first tried to pass a reform to restore economic and diplomatic stability in Rome. While Macrinus’ diplomatic actions brought peace with his opponents, the additional spending and consequent budgetary reforms caused unrest in the Roman army.