Caracalla (145 - 211). Caracalla, formally known as Antoninus, was Roman emperor from 198 to 217. He was a member of the Severan dynasty, the elder son of Septimius Severus and Julia Domna. Co-ruler with his father from 198, he continued to rule with his brother Geta, emperor from 209, after their father's death in 211. His brother was murdered by the Praetorian Guard later that year, supposedly under orders from Caracalla himself, who then reigned afterwards as sole ruler of the Roman Empire. Caracalla's reign featured domestic instability and external invasions by the Germanic peoples. Caracalla's reign became notable for the Antonine Constitution, 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 enacted against the people of 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. Dio Cassius and Herodian present Caracalla as a soldier first and an emperor second. In the 12th century, Geoffrey of Monmouth started the legend of Caracalla's role as the 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 Louis XVI of France. Modern works continue to portray Caracalla as an evil ruler, painting him as one of the most tyrannical of all Roman emperors. Caracalla was born Lucius Septimius Bassianus. He was renamed Marcus Aurelius Antoninus at the age of seven as part of his father's attempt at union with the families of Antoninus Pius and Marcus Aurelius. According to the 4th century historian Aurelius Victor in his Epitome de Caesaribus, he became known by the agnomen Caracalla after a Gallic hooded tunic that he habitually wore and made fashionable. He may have begun wearing it during his campaigns on the Rhine and Danube. Dio generally referred to him as Tarautas, after a famously diminutive and violent gladiator of the time. Caracalla was born in Lugdunum, Gaul, on 4April 188 to Septimius Severus and Julia Domna. Thus he had Punic and Italian paternal ancestry and Arab maternal ancestry. He had a slightly younger brother, Geta, who would briefly rule as co-emperor alongside him. Caracalla's father appointed Caracalla joint Augustus and full emperor from the year 198 onwards. His brother Geta was granted the same title around 209 or 210. In 202 Caracalla was forced to marry the daughter of Gaius Fulvius Plautianus, Fulvia Plautilla, a woman whom he hated, though for what reason is unknown. By 205 Caracalla had succeeded in having Plautianus executed for treason, though he had probably fabricated the evidence of the plot himself. It was then that he banished his wife, whose later killing might have been carried out under Caracalla's orders.