Many of the characters in Nobilissima were figures in real life.  Others are fictional additions (marked with an * below). 

Placidia with Honoria and Valentinian

Placidia with Honoria and Valentinian

Galla Placidia: daughter of Theodosius the Great. Born in Constantinople in 392 AD  

Placidia's Family:
 -- Theodosius the Great, her father 
 -- Honorius: Placidia’s half-brother and Emperor of the Western Empire
 -- Theodosius II: Placidia's nephew, Emperor of the Eastern Empire
 -- Pulcheria: Sister of Theodosius II, Placidia's niece
 -- Serena:  Placidia’s cousin and guardian. Wife of Stilicho
 -- Valentinian:  Placidia’s son, later Emperor Valentinian III
 -- Honoria: Placidia's daughter

 

Emperor Honorius

Emperor Honorius

Romans in the Court, Senate and Church
 -- * Marcus:  Magister Militum 
--  * Aurelia:  Placidia’s best friend and wife of Marcus
 -- Olympius, advisor to Emperor Honorius
 --  * Sylvia:  Placidia’s maidservant
 -- Constantius:  Placidia’s second husband and later co-Emperor with Honorius
 -- * Gardius:  Senator and friend of Placidia
 -- * Severus:  A Senator and friend of Placidia
 --  * Alanus:  young priest
 -- Ursus:  Bishop of Ravenna
 -- Innocent:  Pontifex Maximus
 -- Ingenuus:  Prefect of the province of Narbonensis
 -- Aspar and Ardabur:  Father and son, senior Generals in the Eastern Empire Army
 -- Johannes:  Secretary to Emperor Honorius, later usurper of the Western Empire
 -- Aetius:  Young lawyer, soldier, and later Placidia's Magister Militum

Alaric, King of the Goths.  (Painting by Ludwig Thiersch, public domain, courtesy of Wikipedia)

Alaric, King of the Goths.  (Painting by Ludwig Thiersch, public domain, courtesy of Wikipedia)

The Visigoths
 -- Alaric:  King of the Visigoths
 -- Ataulf: Alaric’s brother in law.  Became King of the Visigoths when Alaric died. Placidia’s first husband
 -- * Felix: Goth army chief and ally of Placidia
 -- Sigeric, tribal chief, briefly usurper King of the Visigoths after Ataulf's murder
 -- Wallia, successor to Ataulf