her grandson's outrageous behaviour could mean the loss of power, Julia Maesa persuaded Elagabalus to accept his young cousin Severus Alexander as caesar (and thus the nominal future augustus). Alexander was popular with the troops, who increasingly objected to Elagabalus's behaviour. Jealous of this popularity, Elagabalus removed the title of caesar from his cousin, which enraged the Praetorian Guard. Elagabalus, his mother, and other advisors close to him were assassinated in a Praetorian Guard camp mutiny. Alexander Severus (222–235) Born Marcus Julius Gessius Bassianus Alexianus in around 208, Alexander was adopted as heir apparent by his slightly older and very unpopular cousin, Elagabalus, at the urging of Julia Maesa, who was the grandmother of both cousins and who had arranged for the emperor's acclamation by the Third Gallica Legion. On March 6, 222, when Alexander was 14, a rumour went around the city's troops that Alexander had been killed, ironically triggering his ascension as emperor. Elagabalus was said to have initiated the rumour or attempted to murder Alexander. The 18-year-old Elagabalus and his mother were taken from the palace, dragged through the streets, murdered and thrown in the river Tiber by the Praetorian Guard, which proclaimed Alexander Severus as Augustus. Ruling from the age of 14 under the influence of his mother, Julia Avita Mamaea, Alexander restored to some extent the moderation that had characterised the rule of Septimius Severus. The rising strength of the Sasanian Empire () heralded perhaps the greatest external challenge that Rome faced in the 3rd century. His prosecution of the war against a German invasion of Gaul led to his overthrow by his own troops, whose regard the 27-year-old had lost during the affair. His death was the epochal event beginning the troubled Crisis of the Third Century, where a succession of briefly-reigning military emperors, rebellious generals, and counter-claimants presided over governmental chaos, civil war, general instability and great economic disruption. He was succeeded by Maximinus Thrax (), the first of a series of weak emperors, each ruling on average only 2 to 3 years, which ended 50 years later with the Tetrarchy instituted in the reign of Diocletian.(). Women The women of the Severan dynasty, beginning with Septimius Severus's wife Julia Domna, were notably active in advancing the careers of their male relatives. Other notable women who exercised power behind the scenes included Julia Maesa, sister of Julia Domna, and Maesa's two daughters Julia