Marcus Aurelius Antoninus (born Lucius Septimius Bassianus, Lugdunum 4 April 188 – On the road between Edessa and Carrhae, 8 April 217), better known by his nickname Caracalla, was Roman emperor from 198 to 217 AD. He was a member of the Severan dynasty, the elder son of Emperor Septimius Severus and Empress Julia Domna. Proclaimed co-ruler by his father in 198, he reigned jointly with his brother Geta, co-emperor from 209, after their father's death in 211. His brother was murdered by the Praetorian Guard later that year under orders from Caracalla, who then reigned afterwards as sole ruler of the Roman Empire. Caracalla found administration to be mundane, leaving those responsibilities to his mother. Caracalla's reign featured domestic instability and external invasions by the Germanic peoples.
Caracalla's reign became notable for the Antonine Constitution (Latin: Constitutio Antoniniana), also known as the Edict of Caracalla, which granted Roman citizenship to all free men throughout the Roman Empire. The edict gave all the enfranchised men Caracalla's adopted praenomen and nomen: "Marcus Aurelius". Domestically, Caracalla became known for the construction of the Baths of Caracalla, which became the second-largest baths in Rome; for the introduction of a new Roman currency named the antoninianus, a sort of double denarius; and for the massacres he ordered, both in Rome and elsewhere in the empire. In 216, Caracalla began a campaign against the Parthian Empire. He did not see this campaign through to completion due to his assassination by a disaffected soldier in 217. Macrinus succeeded him as emperor three days later.
The ancient sources portray Caracalla as a tyrant and as a cruel leader, an image that has survived into modernity. His contemporaries Cassius Dio (c. 155 – c. 235) and Herodian (c. 170 – c. 240) present him as a soldier first and an emperor second. In the 12th century, Geoffrey of Monmouth started the legend of Caracalla's role as king of Britain. Later, in the 18th century, the works of French painters revived images of Caracalla due to apparent parallels between Caracalla's tyranny and that ascribed to king Louis XVI (r. 1774–1792). Modern works continue to portray Caracalla as an evil ruler, painting him as one of the most tyrannical of all Roman emperors.
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At the beginning of 217, Caracalla was still based at Edessa before renewing hostilities against Parthia. On 8 April 217 Caracalla was travelling to visit a temple near Carrhae, now Harran in southern Turkey, where in 53 BC the Romans had suffered a defeat at the hands of the Parthians. After stopping briefly to urinate, Caracalla was approached by a soldier, Justin Martialis, and stabbed to death. Martialis had been incensed by Caracalla's refusal to grant him the position of centurion, and the praetorian prefect Macrinus, Caracalla's successor, saw the opportunity to use Martialis to end Caracalla's reign. In the immediate aftermath of Caracalla's death, his murderer, Martialis, was killed as well.
When Caracalla was murdered, Julia Domna was in Antioch sorting out
correspondence, removing unimportant messages from the bunch so that
when Caracalla returned, he would not be overburdened with duties. Three days later, Macrinus declared himself emperor with the support of the Roman army.
