Caracalla

Caracalla, the elder son of Septimius Severus and Julia Domna, was born at Lugdunum in 188 under the name Lucius Septimius Bassianus. When his father attached the Severan house to the Antonine dynasty by retroactive adoption, the boy was renamed Marcus Aurelius Antoninus, making him the living token of that manufactured cross-dynastic descent; the nickname Caracalla, from a hooded Gallic cloak he favored, was never an official name.

Raised to the rank of Augustus in 198 at the age of ten, he was co-ruler with his father and, from 209, with his younger brother Geta as well. He accompanied Severus on the British campaign and, on their father's death at York in 211, returned to Rome in an uneasy joint reign. The partnership ended within the year: in December 211 Geta was killed by soldiers in the imperial palace, by ancient and consistent testimony at Caracalla's instigation, and his memory was systematically erased.

The most consequential act of the sole reign was the Constitutio Antoniniana of 212, which extended Roman citizenship to virtually all free inhabitants of the empire. Ancient writers ascribed fiscal motives, since citizenship widened liability to inheritance taxes, but whatever its intent the edict transformed the legal character of the Roman world. Caracalla also raised army pay again, introduced a new silver coin of reduced fineness, the antoninianus, and built the enormous baths in Rome that bear his name.

His later years were spent with the army, campaigning on the Rhine and Danube and then in the East, where he cultivated a self-conscious imitation of Alexander the Great. The contemporary historians Cassius Dio and Herodian are hostile witnesses, but the punitive massacre they report at Alexandria in 215 and the harshness of his rule toward the Senate are consistently attested. In April 217, while traveling near Carrhae in Mesopotamia, he was killed by a soldier in a plot arranged by his praetorian prefect Macrinus, who succeeded him; the Severan dynasty was restored the following year through the descendants of Julia Domna's sister.