|Roman imperial dynasties|
Julia Mamaea on a denarius celebrating Felicitas
|Septimius Severus||193 – 198|
|-with Caracalla||198 – 209|
|-with Caracalla and Geta||209 – 211|
|Caracalla and Geta||211 – 211|
|Caracalla||211 – 217|
|Interlude: Macrinus||217 – 218|
|Elagabalus||218 – 222|
|Alexander Severus||222 – 235|
|Severan dynasty family
Year of the Five Emperors
Crisis of the Third Century
Marcus Julius Gessius Marcianus was a Syrian who lived in the 2nd century and 3rd century. He originally came from Arca Caesarea (modern Arqa, Lebanon). Marcianus' career had advanced to the Equestrian order and he became a Promagistrate.
Marcianus married Julia Avita Mamaea, as her second husband. She was the second daughter of the powerful Roman Syrian woman Julia Maesa and the Syrian noble Julius Avitus. Her maternal aunt was Roman empress Julia Domna; her maternal uncle in marriage was Roman emperor Lucius Septimius Severus; her maternal cousins were Roman emperors Caracalla and Publius Septimius Geta and Julia was the maternal aunt to Roman emperor Elagabalus.
Mamaea bore Marcianus two children, a daughter called Theoclia (little is known of her) and a son Marcus Julius Gessius Bassianus Alexianus, later emperor Alexander Severus (208-235). His children were born and raised in Arca Caesarea. Marcianus most probably died, before his son became Roman emperor in 222.