Marcus Aurelius Severus Alexander (1 October 208 – March 235), also known as Alexander Severus, was Roman emperor from 222 until 235. He was the last emperor from the Severan dynasty and was the youngest sole emperor of the united Roman Empire (aged 13).
Alexander became emperor at age 13, succeeding his slain cousin, Emperor Elagabalus as his heir. Alexander and Elagabalus were both grandsons of Julia Maesa, the sister of the empress Julia Domna, who had arranged for Elagabalus's acclamation as emperor by the Third Gallic Legion. Elagabalus had been murdered along with his mother Julia Soaemias by his own guards, who, as a mark of contempt, had the two bodies cast into the Tiber river.
 
Alexander was forced to face his Germanic enemies in the early months of 235. By the time he and his mother arrived, the situation had settled, and so his mother convinced him that to avoid violence, trying to bribe the Germanic army to surrender was the more sensible course of action. According to historians, it was this tactic combined with insubordination from  his own men that destroyed his reputation and popularity. Alexander was thus assassinated together with his mother in early March a mutiny of the Legio XXII Primigenia at Moguntiacum (Mainz) , while at a meeting with his generals.  These assassinations secured the throne for Maximinus.