<P> His reign in Rome has long been known for outrageousness, although the historical sources are few, and in many cases not to be fully trusted . He is said to have smothered guests at a banquet by flooding the room with rose petals; married his male lover - who was then referred as the' Empress's husband'; and married one of the Vestal Virgins . Some say he was transgender, and one ancient text states that he offered half the empire to the physician who could give him female genitalia . </P> <P> The running of the Empire during this time was mainly left to his grandmother and mother (Julia Soamias). Seeing that her grandson's outrageous behavior could mean the loss of power, Julia Maesa persuaded Elagabalus to accept his cousin Alexander Severus as Caesar (and thus the nominal Emperor - to - be). However, Alexander was popular with the troops, who viewed their new Emperor with dislike: when Elagabalus, jealous of this popularity, removed the title of Caesar from his nephew, the enraged Praetorian Guard swore to protect him . Elagabalus and his mother were murdered in a Praetorian Guard camp mutiny . </P> <P> Born Marcus Julius Gessius Bassianus Alexianus, Alexander was adopted as heir apparent by his slightly older and very unpopular cousin, the Emperor Elagabalus at the urging of the influential and powerful Julia Maesa--who was grandmother of both cousins and who had arranged for the emperor's acclamation by the Third Legion . On March 6, 222, when Alexander was just fourteen, a rumor went around the city troops that Alexander had been killed, triggering a revolt of the guards that had sworn his safety from Elegabalus and his ascension as emperor . The eighteen - year - old Emperor Elagabalus and his mother were both taken from the palace, dragged through the streets, murdered and thrown in the river Tiber by the Praetorian Guard, who then proclaimed Alexander Severus as Augustus . </P> <P> Ruling from the age of fourteen under the influence of his able mother, Julia Avita Mamaea, Alexander restored, to some extent, the moderation that characterized the rule of Septimius Severus . The rising strength of the Sasanian Empire (226--651) 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 the troops he was leading, whose regard the twenty - seven - year - old had lost during the campaign . </P>

Which of the following are needed to support a claim about history apex