Julian's "Panegyric In Honour Of Eusebia", the primary source for her family and ancestry, states that "she is of a family line that is pure Greek, from the purest of Greeks, and her city is the
metropolis of Macedonia". Her father was the first member of the family to serve as a
consul. The Panegyric never gives his name, but modern historians identify him with
Flavius Eusebius, consul in 347. This Eusebius is identified elsewhere as a former
Magister Equitum and
Magister Peditum, which means he had served as a military commander of both the
cavalry and
infantry of the
Roman army. The
Prosopography of the Later Roman Empire considers it probable that his consulship came at the end of his military career. He is later styled "
Comes." The Panegyric mentions that Eusebia's father died some time before she married Constantius. Her mother, also unnamed in the speech, did not remarry, but "devoted herself to her children, and won a great reputation for prudence, so great indeed that whereas
Penelope, while her husband was still on his travels and wanderings, was beset by those young suitors… no man however fair and tall or powerful and wealthy ever ventured to approach [Eusebia's mother] with any such proposals. And her daughter the Emperor deemed worthy to live by his side". Eusebia’s two brothers, Flavius Eusebius and Flavius Hypatius, both served as co-consuls in 359, which was attributed to her influence. Eusebius is described as a
rhetor in an
epistle by
Libanius. Libanius identifies Eusebius as governor of the
Hellespont c. 355. He was next sent to
Antioch and then appointed governor of
Bithynia, but held no known offices following his term as consul. Hypatius was possibly
vicarius of the city of Rome in 363. Libanius mentions Hypatius appointed
Praefectus urbi, c. 378–379.
Gregory of Nazianzus mentions Hypatius visiting
Constantinople in 381. He served as
Praetorian prefect of both the
Praetorian prefecture of Italy and the
Praetorian prefecture of Illyricum, c. 382–383. An inscription of
Gortyn,
Crete praises him as the most illustrious of the consuls and praetorian prefects. == Empress ==