Alexander Severus Bust Sculpture Roman Emperor. Alexander Severus (Latin: Marcus Aurelius Severus Alexander Augustus; 1 October 208 – 18 March 235), also known as Severus Alexander, was Roman Emperor from 222 to 235. Not counting the usurpation of Uranius Antoninus, he was the last emperor of the Severan dynasty. Severus Alexander succeeded his cousin Elagabalus upon the latter’s assassination in 222, and was ultimately assassinated himself, marking the epoch event for the Crisis of the Third Century – nearly fifty years of civil wars, foreign invasion, and collapse of the monetary economy. Alexander was the heir apparent to his cousin, the eighteen-year-old Emperor who had been murdered along with his mother by his own guards-and as a mark of contempt, had their remains cast into the Tiber river. He and his cousin were both grandsons of the influential and powerful Julia Maesa, who had arranged for Elagabalus’ acclamation as emperor by the famed Third Gallic Legion. It was the rumor of Alexander’s death that triggered the assassination of Elagabalus. As emperor, Alexander’s peace time reign was prosperous. In military conflict against the rising Sassanid Empire, there are mixed accounts, though the Sassanid threat was checked. However, when campaigning against Germanic tribes of Germania, Alexander apparently alienated his legions by engaging in diplomacy and bribery, and they assassinated him.