Due to his unorthodox behavior, Elagabalus and Julia Soaemias alienated the Praetorian Guard and their favor instead fell on Alexander, Mamaea's son.

[8] Julia Mamaea and her mother Maesa played an instrumental role in the imperial accession of Alexander, then 13 years old, by securing the Praetorians' loyalty to him.

The new regime garnered the approval of surviving historical sources for overturning Elagabalus' measures and reinstating a more traditional form of government.

The historian Herodian and text Historia Augusta characterize Alexander as a mama's boy who never managed to escape her maternal domination but that he resented her love of money.

[15] Though she was credited with her son's principled upbringing and the stability during his early reign,[16] the army and ancient historians attributed Alexander's military shortcomings to Mamaea.

[17] According to Herodian, Mamaea had become jealous of her daughter-in-law, Sallustia Orbiana, whom Alexander married in 225, and whose father Seius Sallustius had been possibly made caesar, because she disapproved that there was another Augusta.

[18] Herodian writes Julia Mamaea had Orbiana expelled from the palace and had her father executed, against the will of Alexander Severus, because his mother had too much influence over him and he obeyed all her orders.

[19] The downfall of Orbiana's father, a result of his hostile relation with Mamaea, and the murder of Ulpian are two episodes which demonstrate the prevalence of political intrigues in Alexander's early reign.

Alexander alienated the Rhine legions by his lack of military prowess and his inflexibility towards pay demands, leading to the troops proclaiming Maximinus Thrax emperor in 235.

While this was considered to be that of Mamaea and Alexander in older traditions, this identification has been doubted, as the representation of the sculptural figures follows the conventions of a married couple.