Yo, Julia

This is about the Roman Empress Julia Domna, wife of the Emperor Severus Septimius (146 CE to 211 CE), and mother of the Emperor Caracalla. Her historic lifetime achievements as an administrator and patron of learning and science are well documented here. The novel also paints a historically accurate picture of Rome in the Year of the Five Emperors (Commodus, Pertinax, Julianus, Clodius Albinus and Septimius Severus), and in particular, recounts the three major battles fought by Severus - the Battle of Issues against Pescennius Niger, then the Siege of Byzantium, which remained loyal to Niger even after his death, and finally the Battle of Lugdunum (modern Lyons, in France) against Clodius Albinus. An excellent read, but there is no English translation as yet.

Synopsis from Open Library.