Marcus Aurelius Severus Antoninus, emperor 212–217, son of Septimius Severus and Julia Domna, nicknamed Caracalla from his Gallic dress. When his father died in Britain in 211, Caracalla and his brother Geta succeeded him. The following year Caracalla had his brother and many of his supporters killed, so as to reign alone. To gain the support of the soldiers, he greatly increased their pay, placing an excessive burden on the state finances. He introduced Eastern cults into Rome, esp. that of the Sun. He was relatively tolerant to the Christians: Tertullian, writing in Caracalla’s lifetime, hinted that he had a Christian nurse, saying that Caracalla was lacte christiano educatus Ad Scap. IV, 5. In his reign we know only of the martyrdom of a Bishop Alexander in Latium AASS Sept., VI, 230-235; BS 1 1961 789-790, some hostile acts against the Christian inhabitants of Osroene, including Bardesanes, and the continuation of the persecution in Africa by the proconsul Scapula, against whom Tertullian wrote Ad Scapulam, denouncing his violence and threatening him with God’s punishment. Caracalla’s most important legislation was the Constitutio Antoniniana of 212, which extended Roman citizenship to free inhabitants of the empire who did not yet have it. He began the construction of his baths at Rome, attempted military operations against the Germans and Parthians, and was assassinated in 217 near Edessa by the prefect Opellius Macrinus. P. Monceaux, Histoire littéraire de l’Afrique chrétienne, Paris 1901; M. Sordi, Il cristianesimo e Roma, Bologna 1965, 233-237; P. Keresztes, The Constitutio Antoniniana and the Persecutions under Caracalla: AJPh 90 1970 446-459; M. Sordi, I Cristiani e l’impero romano, Milan 2 1990; G. Jossa, I cristiani e l’impero romano da Tiberio a Marco Aurelio, Naples 1991; A. Ziolkowski, Storia di Roma, It. tr., Milan 2000.