She was married to Sextus Varius Marcellus, a Syrian Roman of an Equestrian family (meaning not a member of the Roman senate). As members of the imperial Roman family, they lived in Rome, where their numerous children were born. In 217, her cousin emperor Caracalla is killed and Macrinus ascends to the imperial throne. Julia's family is allowed to returned to Syria with whole of their financial assets. They would not let the usurper to stand unopposed. Together with her mother, Julia plotted to substitute Macrinus by her son Varius Avitus Bassianus (Heliogabalus). To legitimise this plot, Julia and her mother spread the rumour that the 13-year-old boy was Caracalla's illegitimate son. In 218 Macrinus is killed and Heliogabalus becomes emperor. Julia then becomes the de facto ruler of Rome, since the teenager was concerned mainly with religious matters. Their rule was not popular and soon discontent arose. Julia Soaemias and Heliogabalus were killed by the Pretorian guard in 222. Julia was later declared public enemy and her name erased from all records.
See also: Women in Rome – Severan dynasty family tree