His predecessor's policies had left Rome's coffers empty and the empire at war with several kingdoms, including Parthia, Armenia, and Dacia.

While Macrinus' diplomatic actions brought about peace with each of the individual kingdoms, the additional monetary costs and subsequent fiscal reforms generated unrest in the Roman military.

Caracalla's aunt, Julia Maesa, took advantage of the unrest and instigated a rebellion to have her fourteen-year-old grandson, Elagabalus, recognized as emperor.

Macrinus was overthrown at the Battle of Antioch on 8 June 218 and Elagabalus proclaimed himself emperor with support from the rebelling Roman legions.

After Macrinus' death, the Senate declared him and his son enemies of Rome and had their names struck from the records and their images destroyed, a procedure known as damnatio memoriae.

Macrinus was born in Caesarea (modern Cherchell, Algeria) in the Roman province of Mauretania Caesariensis to an equestrian family of Berber origins.

In April, Caracalla left the winter military camp at Edessa to visit a temple of Luna near the site of the battle of Carrhae and was accompanied only by his personal guard, which included Macrinus.

[10] The story that was told indicated that on 8 April, while travelling to the temple, Caracalla was stabbed to death by Justin Martialis, a soldier who was later claimed to have been recruited by Macrinus to commit the murder.

[31][32] Macrinus settled a peace treaty with them by returning the crown and loot to Khosrov's son and successor Tiridates II and releasing his mother from prison, and by restoring Armenia to its status as a client kingdom of Rome.

[33] In matters of foreign policy, Macrinus showed a tendency towards settling disputes through diplomacy and a reluctance to engage in military conflict, though this may have been due more to the lack of resources and manpower than to his own personal preference.

The soldiers that were already enlisted during Caracalla's reign enjoyed exorbitant payments which were impossible for Macrinus to reduce without risking a potential rebellion.

Instead, Macrinus allowed the enlisted soldiers to retain their higher payments, but he reduced the pay of new recruits to the level which had been set by Severus.

By this time Julia Domna was suffering from a presumed advanced stage of breast cancer and she soon died in Antioch after starving herself.

[43][44] Soldiers from Legio III Gallica (Gallic Third Legion), that had been stationed at the nearby camp of Raphanea, often visited Emesa and went to see Elagabalus perform his priestly rituals and duties while there.

[46] Upon Elagabalus' revolt, Macrinus travelled to Apamea and conferred the title of Augustus onto his son, Diadumenianus, and made him co-emperor.

[49] His son and co-emperor Diadumenianus, sent to the care of Artabanus IV of Parthia, was himself captured in transit at Zeugma and killed in June 218.

[21] Macrinus, upon learning of his son's death, tried to escape captivity, but he injured himself in the unsuccessful attempt[49] and was afterward executed in Cappadocia; his head was sent to Elagabalus.

[19] In the film Gladiator II (2024), Denzel Washington portrays the character "Macrinus", who is loosely inspired by the historical figure.

[51] The choice of Washington garnered controversy and sparked criticism in Algeria, where many people denounced a "blackwashing" of the historical Berber character and argued that "Macrinus was not of sub-Saharan African origin.