 By 221 Elagabalus ' eccentricities , particularly his relationship with Hierocles , increasingly provoked the soldiers of the Praetorian Guard . When Elagabalus ' grandmother Julia Maesa perceived that popular support for the emperor was waning , she decided that he and his mother , who had encouraged his religious practices , had to be replaced . As alternatives , she turned to her other daughter , Julia Avita Mamaea , and her daughter 's son , the thirteen @-@ year @-@ old Severus Alexander . 
