Political map of Europe & the Mediterranean summer 216 (Caracalla’s Parthian Campaign): Following his Germanic War, Caracalla headed east to campaign against Parthia (Parthian war of Caracalla), now splintered between Shah Vologases VI (Vologases VI of Parthia), the usurper Artabanus IV (Artabanus IV of Parthia), and the insurgent Sasanians (Ardashir I). After Vologases agreed to cede political refugees to him and Artabanus agreed—or refused, sources vary—to give him his daughter in marriage, Caracalla attacked Artabanus and seized the city of Arbela (Erbil), the proposed site of the wedding.