Political map of Europe & the Mediterranean September 213 (Caracalla’s Germanic War): Technically Caracalla succeeded his father (Septimius Severus) with his brother Geta as co-emperor (211) (Geta (emperor)), but Caracalla was always more dominant and that December he had Geta murdered. Caracalla then extended Roman citizenship to all free men in the Empire (Constitutio Antoniniana), allowing him to raise more taxes to pay for the massive bonuses he was granting the legions. Responding to a request for aid from the Alemanni, Caracalla traveled to Germania in 213, where he occupied and massacred the Alemanni and fought their neighbors, the Cenni (Chatti). Although this temporarily stabilized the northern frontier, Roman cruelty would not be forgotten.