Caracalla (named for a Gallic cloack that he wore) lived from 186 to 217 A.D. Roman Emperor from 211 to 217. Became emperor upon the death of his father Severus.
Was originally supposed to rule with his brother Geta, but Caracalla murdered his brother along with many others to consolidate power. He was personally a vicious monster, but was a successful military leader and supported by the troops after greatly raising their pay to a level difficult to support. He issued a new coin to cover that expense, a 2 denarii, but it actually weighed only 1 and 2/3rds. He also granted Roman citizenship to almost all free inhabitants of the empire again to help raise more taxes since Roman citizens paid an inheritance tax. Unlike earlier time periods, by this point in history, Roman citizenship had been so watered down that it meant very little.
Militarily he repelled an invasion by the barbarian Alemanni in southern Germany in 213, and drove back back invading Goths in 214. He reconquered Armenia and Mesopotamia from Parthian control. While preparing to invade Parthia, he was murdered by an officer of the imperial bodyguard while he was relieving himself, either because Caracalla had recently had the officer's brother murdered or because he didn't promote him to centurion as he desired. In any case the killer was shot dead as he tried to escape by trained archers.